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Introduction To Graphs

Class 8th Mathematics NCERT Exemplar Solution
Exercise
  1. Comparison of parts of a whole may be done by aA. bar graph B. pie chart C. Liner…
  2. A graph that displays data that changes continuously over periods of time isA.…
  3. In the given graph the coordinates of point x are A. (0, 2) B. (2, 3) C. (3, 2)…
  4. In the given graph the letter that indicates the point (0, 3) is A. P B. Q C. R…
  5. The point (3, 4) is at a distance ofA. 3 from both the axis B. 4 from both the…
  6. A point which lies on both the axis is ______A. (0, 0) B. (0, 1) C. (1, 0) D. (1,…
  7. The coordinates of a point at a distance of 3 units from the x axis and 6 units…
  8. In the given figure the position of the book on the table may be given by A. (7,…
  9. Data was collected on a student’s typing rate and graph was drawn as shown below.…
  10. Which graphs of the following represent the table below? |c|c|c|c|c|c|…
  11. _________ displays data that changes continuously over periods of time. Fill in…
  12. The relation between dependent and independent variables is shown through a…
  13. We need________ coordinates for representing a point on the graph sheet. Fill in…
  14. A point in which the x-coordinate is zero and y-coordinate is non-zero will lie…
  15. The horizontal and vertical line in a line graph are usually called…
  16. the process of fixing a point with the help of the coordinates is known as…
  17. the distance of any point from the y-axis is the _________ coordinate. Fill in…
  18. All points with y-coordinates as zero lie on the _________. Fill in the blanks…
  19. For the point (5,2), the distance from the x-axis is _________ units. Fill in…
  20. The x-coordinate of any point lying on the y-axis will be _________. Fill in the…
  21. The y-coordinate of the point (2,4) is _________. Fill in the blanks to make the…
  22. In the point (4, 7), 4 denotes the _________. Fill in the blanks to make the…
  23. A point has 5 as its x-coordinates and 4 as its y-coordinate. Then the…
  24. In the coordinates of a point, the second number denotes the _________. Fill in…
  25. The point where the two axes intersect is called the _________. Fill in the…
  26. For fixing a point on the graph sheet we need two coordinates. State whether the…
  27. A line graph can also be a whole unbroken line. State whether the given…
  28. The distance of any point from the x-axis is called the x-coordinate. State…
  29. The distance of the point (3,5) from the y-axis is 5. State whether the given…
  30. The ordinate of a point is its distance from the y-axis. State whether the given…
  31. In the point (2, 3) 3 denotes the y-coordinate. State whether the given…
  32. The coordinates of the origin are (0,0). State whether the given statements are…
  33. The points (3,5) and (5,3) represent the same point. State whether the given…
  34. The y-coordinate of any point lying on the x-axis will be zero. State whether…
  35. Match the coordinates given in Column A with the items mentioned in column B.…
  36. Match the coordinates given in Column A with the items mentioned in column B.…
  37. From the given graph, choose the letters that indicate the location of the…
  38. Find the coordinates of all letters in the graph given below.
  39. Plot the given points on a graph sheet. A) (5,4) B) (2,0) C) (3,1) D) (0,4) E)…
  40. Study the given map of a zoo and answer the following questions. A) Give the…
  41. Write the x-coordinate (abscissa) of each of the given points. A) (7,3) B) (5,7)…
  42. Write the Y-coordinate (ordinate) of each of the given points. A) (3,5) B) (4,0)…
  43. (1,2),(2,4) (3,6),(4,8). Plot the given points on a graph sheet and check if…
  44. (1,1),(1,2),(2,1),(2,2). Plot the given points on a graph sheet and check if…
  45. (4,2),(2,4),(3,3), (5,4). Plot the given points on a graph sheet and check if…
  46. If y-coordinate is 3 times x-coordinate, form a table for it and draw a graph.…
  47. Make a line graph for the area of a square as per the given table. |c|c|c|c|c|…
  48. The cost of a note book is Rs 10. Draw a graph after making a table showing cost…
  49. Explain the situation represented by the following distance-time graphs. l l…
  50. Complete the given tables and draw a graph for each.
  51. |l|l|l|l| x&1&2&4&6 y = x-1&0& Complete the given tables and draw a graph for…
  52. Study the given graph (a) and (b) and complete the corresponding tables below.…
  53. Draw a graph for the radius and circumference of circle using a suitable scale.…
  54. The graph shows the maximum temperatures recorded for two consecutive weeks of a…
  55. The graph below gives the actual and expected sales of cars of a company for 6…
  56. The graph given below shows the marks obtained out of 10 by Sonia in two…
  57. Find the coordinates of the vertices of the given figures.
  58. Study the graph given below of a person who started from his home and returned…
  59. Plot a line graph for the variables p and q where p is two times q i.e, the…
  60. Study the graph and answer the questions that follow. n A) What information does…
  61. Study the distance-time graph given below for a car to travel to certain places…
  62. Locate the points A (1, 2), B (4, 2) and C (1, 4) on a graph sheet taking…
  63. Locate the points A(1,2), B(3,4) and C(5,2) on a graph sheet taking suitable…
  64. Locate the points P (3, 4), Q (1, 0), R (0, 4), S (4, 1) on a graph sheet and…
  65. The graph given below compares the sales of ice creams of two vendors for a…
  66. The table given below shows the temperatures recorded on a day a different…
  67. The following table gives the growth chart of a child. Draw a line graph for the…
  68. The following is the time-distance graph of Sneha’s walking. A) When does Sneha…
  69. Draw a parallelogram ABCD on a graph paper with the coordinates given in Table…
  70. Plot the points (2,4) and (4,2) on a graph paper, then draw a line segment…
  71. The following graph shows the change in temperature of a block of ice when…
  72. The following graph shows the number of people present at a certain shop at…
  73. A man started his journey on his journey on his car from location A and came…
  74. The following graph shows the journey made by two cyclists, one from town A to B…
  75. Ajita starts off from home at 07.00 hours with her father on a scooter that goes…
  76. Draw the graph using suitable scale to show the annual gross profit of a company…
  77. The following chart gives the growth in height in length of percentage of full…
  78. The table shows the data collected for Dhruv’s walking on a road. |c|c|c|c|c|c|…
  79. Observe the given carefully and complete the table given below. |c|c|c|c|c|c|…
  80. This graph shows the per cent of students who dropped out of school after…
  81. Observe the toothpick pattern given below: pi _ 3 pi underbrace pi pattern4 (a)…
  82. Consider this input/output table. |c|c|c|c|c| &1&2&4&5&7 &2&5&11&14&20 (a) Graph…
  83. This graph shows a map of an island just off the coast of a continent. The point…
  84. As part of his science project, Prithvi was supposed to record the temperature…
  85. The graph given below compares the price (in Rs) and weight of 6 bags (in kg) of…
  86. The points on the graph below represent the height and weight of the donkey,…
  87. The two graphs below compare Car A and Car B. The left graph shows the…
  88. Sonal and Anmol made a sequence of tile designs from square white tiles…
  89. Sonal and Anmol then made another sequence of the designs. Three of the designs…
  90. Create a table like the one shown If an estimate is the same as the actual…

Exercise
Question 1.

Comparison of parts of a whole may be done by a
A. bar graph

B. pie chart

C. Liner graph

D. line graph


Answer:

A pie-graph\chart is the used to compare parts of a whole as a circle represents the whole. Each non-intersecting adjacent sector represents of the part of the circle/data.


Question 2.

A graph that displays data that changes continuously over periods of time is
A. bar graph

B. pie chart

C. histogram

D. line graph


Answer:

A line graph displays data which changes continuously over period of time such as speed or distance covered. This graph displays the relationship between two varying quantities.


Under this graph a single line is used to join all the points plotted on the graph paper hence giving more precise depiction of the data to be interpreted.


Question 3.

In the given graph the coordinates of point x are


A. (0, 2)

B. (2, 3)

C. (3, 2)

D. (3, 0)


Answer:

To find out the co-ordinates of the point X, we draw perpendicular from point X to the x-axis and y-axis simultaneously, and would check at what distance from the origin, they meet both the axis.


The perpendicular drawn from X to x-axis meets at 3units from origin so x co-ordinate of X is 3


Similarly, y co-ordinate is 2


The co-ordinates of the point X are (3,2)


Question 4.

In the given graph the letter that indicates the point (0, 3) is


A. P

B. Q

C. R

D. S


Answer:

The co-ordinates of points R are (0,3) as the point lies on y-axis so its x co-ordinate is 0 and from the origin it is at distance o f3 units so its y co-ordinates is 3.


The co-ordinates of S are (3,3) and P are (3,0)


Question 5.

The point (3, 4) is at a distance of
A. 3 from both the axis

B. 4 from both the axis

C. 4 from the X axis and 3 from y axis

D. 3 from x axis and from 4 y axis


Answer:

The point (3, 4) is at the distance from 3 units from the y axis and 4 units from the x axis.


When the co-ordinates are written the first number indicates distance on x axis or the y co-ordinate and second number indicates distance on y axis or the x co-ordinate from the origin.


Question 6.

A point which lies on both the axis is ______
A. (0, 0)

B. (0, 1)

C. (1, 0)

D. (1, 1)


Answer:

Since both the axis are perpendicular to each other they intersect at single point which is termed as origin and its co-ordinates are (0, 0). So (0, 0) is the single point which lies on both the axis.


Question 7.

The coordinates of a point at a distance of 3 units from the x axis and 6 units from the y axis is
A. (0, 3)

B. (6, 0)

C. (3, 6)

D. (6, 3)


Answer:

As the distance from x axis gives y co-ordinate and distance from the y axis gives x co-ordinates, the co-ordinates of the given point are (6,3).



Question 8.

In the given figure the position of the book on the table may be given by


A. (7, 3)

B. (3, 7)

C. (3, 3)

D. (7, 7)


Answer:

The book is at the distance of 3 units from the y axis so its x co-ordinate is 3 and at the distance of 7 units from the x-axis, so its y co-ordinate is 7. Hence, the required point is (3, 7).


Question 9.

Data was collected on a student’s typing rate and graph was drawn as shown below. Approximately how many words had this student typed in 30 seconds?


A. 20

B. 24

C. 28

D. 34


Answer:

The time taken is denoted on x axis and the number of words types are on y axis. To calculate words types in 30 seconds. We look for the point on the line graph which corresponds 30 on the x axis and from that point on the graph, draw perpendicular on y axis to find the number of words typed. The Answer comes out to be approximately 28 words in 30seconds.


Question 10.

Which graphs of the following represent the table below?


A.

B.

C.

D.


Answer:

Here length of the side of the square are given on x axis and perimeter is given on y axis.


From the table given in question the points to be plotted on line graph are (1, 4), (2,8) ,(3, 12), (4, 16) and (5, 20)


After checking the graphs given, these points are plotted in the graph number D. Hence the solution is option D


Question 11.

Fill in the blanks to make the statements true.

_________ displays data that changes continuously over periods of time.


Answer:

line graph


A line graph displays data which changes continuously over period of time such as speed or distance covered. This graph displays the relationship between two constantly varying quantities.



Question 12.

Fill in the blanks to make the statements true.

The relation between dependent and independent variables is shown through a ___________.


Answer:

graph


A graph is the representation of data between two variables where one is independent variable and other is dependent variable. The graph shows how change in quantity of independent variable brings in change in quantity of dependent variable.



Question 13.

Fill in the blanks to make the statements true.

We need________ coordinates for representing a point on the graph sheet.


Answer:

a pair (two)


The x coordinate and the y co-ordinate are the two or a pair of point required to plot the point on graph paper. The distance of point from x axis makes y co-ordinate and distance of point from y axis makes x co-ordinate.



Question 14.

Fill in the blanks to make the statements true.

A point in which the x-coordinate is zero and y-coordinate is non-zero will lie on the ________ .


Answer:

y axis


The x co-ordinate is zero means the distance of point from y axis is zero which means it lies on y axis itself at a certain point from the origin.



Question 15.

Fill in the blanks to make the statements true.

The horizontal and vertical line in a line graph are usually called _________.and _________.


Answer:

x axis and y axis, respectively


The horizontal line in a line graph is called as x axis and vertically line is called as y axis which are two mutually perpendicular lines intersecting at Origin (0,0)



Question 16.

Fill in the blanks to make the statements true.

the process of fixing a point with the help of the coordinates is known as _________ Of the point.


Answer:

the two points required to plot any point on the graph are its two co-ordinates namely x and y. these co-ordinates fixes the exact position of the point on the graph which actually is the distance of the point from the x axis and y axis. This fixing the position of the point is called as plotting of the point on graph.



Question 17.

Fill in the blanks to make the statements true.

the distance of any point from the y-axis is the _________ coordinate.


Answer:

x co-ordinate


How much distance the point to be plotted is from the y axis is actually the x co-ordinate and similarly, how much distance far away the point is from the x axis is its y co-ordinate or ordinate.



Question 18.

Fill in the blanks to make the statements true.

All points with y-coordinates as zero lie on the _________.


Answer:

x axis


Y co-ordinate depicts the Distance of the given point from the x axis and if the y co-ordinates are zero that means the distance from x axis is zero i.e; the point is on x axis itself.



Question 19.

Fill in the blanks to make the statements true.

For the point (5,2), the distance from the x-axis is _________ units.


Answer:

2 units


Since the y co-ordinate shows the distance from the x axis hence the point (5,2) means the distance from the x axis is 2 units.



Question 20.

Fill in the blanks to make the statements true.

The x-coordinate of any point lying on the y-axis will be _________.


Answer:

zero (0)


x co-ordinate represents the distance from the y axis is zero therefore the x coordinates of point any point on y axis will be zero.



Question 21.

Fill in the blanks to make the statements true.

The y-coordinate of the point (2,4) is _________.


Answer:

The y coordinate is the distance of the point from the x axis. In the ordered pair, the second number always denotes the y co-ordinate so; here the y co-ordinate will be 4 units.



Question 22.

Fill in the blanks to make the statements true.

In the point (4, 7), 4 denotes the _________.


Answer:

Here (4, 7) is an ordered pair of point so 4 denote the x co-ordinate or the distance from the y axis.



Question 23.

Fill in the blanks to make the statements true.

A point has 5 as its x-coordinates and 4 as its y-coordinate. Then the coordinates of the point are given by _________.


Answer:

The co-ordinates of a point are (5, 4)


X coordinate is written on the first place followed by y co-ordinate in an ordered pair of point,



Question 24.

Fill in the blanks to make the statements true.

In the coordinates of a point, the second number denotes the _________.


Answer:

y co-ordinate


In an ordered pair of point, x coordinate is written on the first place followed by y co-ordinate so the second number denotes the y co-ordinate or the distance of the point from the x axis.



Question 25.

Fill in the blanks to make the statements true.

The point where the two axes intersect is called the _________.


Answer:

origin


The intersecting point of the two mutually perpendicular x axis and y axis is called as origin with coordinates as (0,0)



Question 26.

State whether the given statements are true (T)or false (F).

For fixing a point on the graph sheet we need two coordinates.


Answer:

True

For fixing a point on the graph sheet we need two coordinates because we draw graph in (x, y) form. One point required for x – axis and one point for y – axis. x – axis goes from left and right and y – axis goes from up and down.


Hence, it is true.




Question 27.

State whether the given statements are true (T)or false (F).

A line graph can also be a whole unbroken line.


Answer:

False

A line graph consists of bits of line segments joined consecutively. The graph which have a whole unbroken line called linear graphs.


Hence, it is not true.



Question 28.

State whether the given statements are true (T)or false (F).

The distance of any point from the x-axis is called the x-coordinate.


Answer:

False

The distance of any point from x – axis is called its y – coordinate and the distance of a point from y – axis is called its x – coordinate.


Hence, it is not true.



Question 29.

State whether the given statements are true (T)or false (F).

The distance of the point (3,5) from the y-axis is 5.


Answer:

False

Given point is (3, 5)


⇒ Comparing with (x, y) form


⇒ x = 3 and y = 5


⇒ As we know that distance of a point from y – axis is called its x – coordinate


∴ distance of the point from y – axis will 3.


Hence, it is not true.



Question 30.

State whether the given statements are true (T)or false (F).

The ordinate of a point is its distance from the y-axis.


Answer:

False

Ordinate also known as y – coordinate of a point. And it is defined as distance from x – axis.


Hence, it is not true.



Question 31.

State whether the given statements are true (T)or false (F).

In the point (2, 3) 3 denotes the y-coordinate.


Answer:

True

Ordinate is distance from x – axis.


⇒ distance from x – axis = y – coordinate.


∵ distance from x – axis is 3.


∴ ordinate will be 3.


Hence, it is true.



Question 32.

State whether the given statements are true (T)or false (F).

The coordinates of the origin are (0,0).


Answer:

True

Axes intersect when both x and y are zero. Centre of the coordinate system called origin. Coordinates of the origin are (0, 0).


Hence, it is true.



Question 33.

State whether the given statements are true (T)or false (F).

The points (3,5) and (5,3) represent the same point.


Answer:

False

The points (3,5) and (5,3) represents different points.


⇒ In Point (3,5):


X – coordinate = 3


Y – coordinate = 5


⇒ In point (5,3)


X – coordinate = 5


Y – coordinate = 3


Hence, it is not true.



Question 34.

State whether the given statements are true (T)or false (F).

The y-coordinate of any point lying on the x-axis will be zero.


Answer:

True

Points that lies on axis does not lie in any quadrant. If a point lies on y – axis then its x – coordinate will be zero. And if a point lies on x – axis then its y – coordinate will be zero.


Hence, it is not true.



Question 35.

State whether the given statements are true (T)or false (F).

Match the coordinates given in Column A with the items mentioned in column B.



Answer:

(1→D), (2→F), (3→E), (4→A ), (5→B), (6→C)

1. Given Point is (0,5)


Distance from x – axis = y – coordinate


∴ Distance from x – axis = 5


2. Given Point is (2,3)


Distance from y – axis = x – coordinate


∴ Distance from y – axis = 2


3. Given Point is (4,8)


Distance from x – axis = y – coordinate


∴ Distance from x – axis = 8


Distance from y – axis = x – coordinate


∴ Distance from y – axis = 4


∴ we can say that y – coordinate is double of x – coordinate.


4. Given Point is (3,7)


Here, x – coordinate = 3 and y – coordinate = 7.


⇒ y – coordinate = 2× 3 + 1


⇒ Thus, y – coordinate = 2× (x – coordinate) + 1.


5. Given Point is (0,0)


Centre of the coordinate system is called origin. Coordinates of origin are (0,0)


6. Given Point is (5,0)


Here, x – coordinate = 5 and y – coordinate = 0.


∴ only y – coordinate is zero.



Question 36.

State whether the given statements are true (T)or false (F).

Match the coordinates given in Column A with the items mentioned in column B.



Answer:

(A→ ii), (B→ iii), (C→ i), (D→ v), (E→ vi), (F→ iv)

In a given coordinate system P(x, y).


⇒ ‘x’ represents abscissa and ‘y’ represents ordinate.


A. Given Point is (7, 0)


Here, abscissa i.e. x – coordinate = 7 and ordinate i.e. y – coordinate = 0.


⇒ Thus, ordinate is zero.


B. Given Point is (11,11)


Here, abscissa i.e. x – coordinate = 11 and ordinate i.e. y – coordinate = 11.


⇒ Thus, ordinate is equal to abscissa.


C. Given Point is (4,8)


Here, abscissa i.e. x – coordinate = 4 and ordinate i.e. y – coordinate = 8.


⇒ Thus, ordinate is double the abscissa.


D. Given Point is (6,2)


Here, abscissa i.e. x – coordinate = 6 and ordinate i.e. y – coordinate = 2.


⇒ Thus, abscissa is triple the ordinate.


E. Given Point is (0,9)


Here, abscissa i.e. x – coordinate = 0 and ordinate i.e. y – coordinate = 9.


⇒ Thus, abscissa is zero.


F. Given Point is (6,3)


Here, abscissa i.e. x – coordinate = 6 and ordinate i.e. y – coordinate = 3.


⇒ Thus, abscissa is double the ordinate.



Question 37.

From the given graph, choose the letters that indicate the location of the points given below.



A) (2,0)

B) (0,4)

C) (5,1)

D) (2,6)

E) (3,3)


Answer:

A) F is the point which indicates the location of the point (2,0)


As the x coordinate is 2 and y-coordinate is 0.


Hence F is the point which indicates the location of the point (2,0).


B) A is the point which indicates the location of the point (0,4)


As the x coordinate is 0


The y- coordinate is 4


Hence F is the point which indicates the location of the point (0,4).


C) B is the point which indicates the location of the point (5,1)


As the x coordinate is 5


The coordinate is 1


Hence F is the point which indicates the location of the point (5,1).


D) B is the point which indicates the location of the point (5,1)


As the x coordinate is 5


The coordinate is 1


Hence F is the point which indicates the location of the point (5,1).


E) E is the point which indicates the location of the point (3,3)


As the x coordinate is 3


The coordinate is 3


Hence F is the point which indicates the location of the point (3,3).



Question 38.

Find the coordinates of all letters in the graph given below.



Answer:

(i) Point A is lying on 0 on x axis and 7.5 on y axis

The coordinates of the point A is (0,7.5)


(ii) Point B is lying on 4 in x axis and 5 in y axis


The coordinates of the point B is (4,5)


(iii) Point C is lying on 7.5 in x axis and 2.5 in y axis


The coordinates of the point C is (7.5,2.5)


(iv) Point D is lying on 11 in x axis and 0 in y axis


The coordinates of the point D is (11,0)


(v) Point E is lying on 14.5 in x axis and 6.5 in y axis


The coordinates of the point E is (14.5,6.5)


(vi) Point F is lying on 18 in x axis and 9.5 in y axis


The coordinates of the point F is (18,9.5)



Question 39.

Plot the given points on a graph sheet.

A) (5,4)

B) (2,0)

C) (3,1)

D) (0,4)

E) (4,5)


Answer:

Draw the x and y axis then plot the given points according to the coordinates.




Question 40.

Study the given map of a zoo and answer the following questions.



A) Give the location of lions in the zoo.

B) (D,F) and (C,D) represent locations of which animals in the zoo?

C) Where are the toilets located?

D) Give the location of canteen.


Answer:

A) As the x coordinate is lying on A on x axis


The y coordinate is lying on f on y axis


The coordinates of that point be (x,y)(A,f)


Hence the location of lions in the zoo is at the point (A,f)


B) (D,f)→ Monkey


As the coordinate x is D and coordinate y is f i.e., (D,f)


Which is already representing monkeys.


(C,d)→ Elephant


As the coordinate x is C and coordinate y is d i.e., (C,d)


Which is already representing elephants


C) As the x coordinate is lying on 0 on x axis


The y coordinate is lying on e on y axis


The coordinates of that point be (x,y)(0,e)


Hence the location of lions in the zoo is at the point (0,e)


D) As the x coordinate is lying on C on x axis


The y coordinate is lying on c on y axis


The coordinates of that point be (x,y)(C,c)


Hence the location of lions in the zoo is at the point (C,c)



Question 41.

Write the x-coordinate (abscissa) of each of the given points.

A) (7,3)

B) (5,7)

C) (0,5)


Answer:

A) 7 which is on the left is the x coordinate the point which is


in the form of (x,y)


B) 5 which is on the left is the x coordinate the point which is


in the form of (x,y)


C) 0 which is on the left is the x coordinate the point which is


in the form of (x,y)



Question 42.

Write the Y-coordinate (ordinate) of each of the given points.

A) (3,5)

B) (4,0)

C) (2,7)


Answer:

A) 5 which is on the right is the y coordinate the point which is


in the form of (x,y)


B) 0 which is on the right is the y coordinate the point which


is in the form of (x,y)


C) 7 which is on the right is the y coordinate the point which


is in the form (x,y)



Question 43.

Plot the given points on a graph sheet and check if the points lie on a straight line, name the shape they for when joined in the given order.

(1,2),(2,4) (3,6),(4,8).


Answer:


The points lie on a straight line.



Question 44.

Plot the given points on a graph sheet and check if the points lie on a straight line, name the shape they for when joined in the given order.

(1,1),(1,2),(2,1),(2,2).


Answer:


It is not in a straight line, when joined in the given order a semi arch is formed.



Question 45.

Plot the given points on a graph sheet and check if the points lie on a straight line, name the shape they for when joined in the given order.

(4,2),(2,4),(3,3), (5,4).


Answer:


it is not a straight line, when joined in the given order (also AD) a triangle is formed.



Question 46.

If y-coordinate is 3 times x-coordinate, form a table for it and draw a graph.


Answer:

Let the x coordinate be x

Y coordinate is 3x (according to the given question)


Forming a table,


Let x = 1(x coordinate)


Y = 3x = 31 = 3 (y coordinate)


Let x = 2(x coordinate)


Y = 3x = 32 = 6 (y coordinate)


Let x = 3(x coordinate)


Y = 3x = 33 = 9 (y coordinate)


Let x = 1(x coordinate)


Y = 3x = 34 = 12 (y coordinate)





Question 47.

Make a line graph for the area of a square as per the given table.



Is it a liner graph?


Answer:


Plot the given points on the graph where x axis indicates sides of a square and y axis indicates area of the square.


No, it is not a linear graph because it is not having shape of line. As all the points that make up this graph are not collinear, or in other words, not on the same line



Question 48.

The cost of a note book is Rs 10. Draw a graph after making a table showing cost of 2, 3, 4 ... note books. Use it to find

A) the cost of 7 notebooks.

B) The number of note books that can be purchased with Rs50.


Answer:

A) Given cost of one notebook = Rs. 10


Cost of 7 notebooks = 710 = Rs. 70


B) Given cost of one notebook = Rs. 10


Number of books for Rs. 50 = = 5



Question 49.

Explain the situation represented by the following distance-time graphs.







Answer:

(a) As the distance increase time also increase with equal intervals


(b) The slope part represents that distance increase time also increase and the remaining part represents that distance is


constant for long time.


(c) Distance increase time also increase unequal intervals.



Question 50.

Complete the given tables and draw a graph for each.



Answer:

A)



Here, y = 3x + 1


When x = 2,


y = 3(2) + 1 = 6 + 1 = 7


When x = 3,


y = 3(3) + 1 = 9 + 1 = 10


The points in the graph are given as:


A = (0,1)


B = (1,4)


C = (2,7)


D = (3,10)



The line segments:




Question 51.

Complete the given tables and draw a graph for each.



Answer:


Here, y = x – 1


When x = 2,


y = 2 – 1 = 1


When x = 4,


y = 4 – 1 = 3


When x = 6,


y = 6 – 1 = 5


The points in the graph are given as


A = (1, 0)


B = (2, 1)


C = (4, 3)


D = (6, 5)



The line segments are




Question 52.

Study the given graph (a) and (b) and complete the corresponding tables below.

A)



B)



Answer:

A)



By drawing the lines parallel to the y-axis and the x-axis, we can see at what point they intersect the given graph.


Step 1 :For x = 1, we draw a line parallel to the y-axis at 1 and see where it intersects the graph.


Step 2 :From the point of intersection, we draw another line which is parallel to the x-axis.


Step 3 :The point at which this line intersects the y-axis is the value of y at x = 1.


Similarly, we can find the values of y for each of the given values of x by following the above steps.


B)



Following the steps mentioned above, we can find the values of y for each of the given values of x.



Question 53.

Draw a graph for the radius and circumference of circle using a suitable scale.

(Hint : Take radius = 7,14,21 units and so on) From the graph,

A) Find the circumference of the circle when radius is 42 units.

B) At what radius will the circumference of the circle be 220 units?


Answer:

Circumference = 2r

The circumference of a circle depends on the radius of a circle.


So, we plot the circumference on the y-axis as it is the dependent variable and the radius on the x-axis as it is the independent variable.


∴ We get the equation in terms of x and y as


y = 2x


When x = 0,


y = 2 × 0 = 0


When x = 7,


y = 2 × 7 = 2 × × 7 = 44


When x = 14,


y = 2 × 14 = 2 × × 14 = 88


When x = 21,


y = 2 × 21 = 2 × × 21 = 132



The points in the graph are given as


A = (0, 0)


B = (7, 44)


C = (14, 88)


D = (21, 132)



The line segments are



A) When the radius is 42 units, i.e. x = 42,


y = 264 (from the graph)


B) The circumference of the circle will be 220 units when the radius is 35 units (from the graph)



Question 54.

The graph shows the maximum temperatures recorded for two consecutive weeks of a town. Study and answer the questions that follow.



A) What information is given by the two axes?

B) In which week was the temperature higher on most of the days?

C) On which day was the temperature same in both the weeks?

D) On which day was the difference in temperatures the maximum for both the weeks?

E) What were the temperatures for both the weeks on Thursday?

F) On which day was the temperature highest for the second week?


Answer:

A) The x-axis gives the days of the week on which the temperatures were recorded; whereas the y-axis gives the maximum temperature that was recorded on a particular day.


B) The temperature was higher on most of the days in the first week. If we compare the graphs of the two weeks, we see that the temperature in the first week is more than the temperature in the second week for everyday except Monday and Wednesday.


C) The temperature was same on Wednesday in both the weeks. There is only on point on Wednesday unlike all the other days which have two different points for temperatures in different weeks.


D) The difference in the temperatures was maximum, i.e. 7°C, for both the weeks on Friday.


Difference on Sunday = 35 – 32 = 3°C.


Difference on Monday = 35 – 31 = 4°C.


Difference on Tuesday = 38 – 33 = 5°C.


Difference on Wednesday = 36 – 36 = 0°C.


Difference on Thursday = 37 – 34 = 3°C.


Difference on Friday = 39 – 32 = 7°C.


Difference on Saturday = 37 – 33 = 4°C.


E) The temperature on Thursday for the first week was 37°C and that for the second week was 34°C.


F) The temperature was highest, i.e. 36°C, for the second week on Wednesday.



Question 55.

The graph below gives the actual and expected sales of cars of a company for 6 months. Study the graph and answer the questions that follow.



A) In which month was the actual sales same as the expected sales?

B) For which month(s) was (were) the difference in actual and expected sales the maximum?

C) For which month(s) was (were) the difference in actual and expected sales the least?

D) What was the total sales of cars in the months-Jan, Feb. And March?

E) What is the average sales of cars in the last three months?

F) Find the ratio of sales in the first three months of the last three months.


Answer:

A) The actual sales was the same as the expected sales in the month of April. This is because the graph has only one point for the month of April which indicates that the value of the y-axis is the same for both the graphs.


B) The difference in actual and expected sales was maximum, i.e. 75, in the month of March.


Difference in January = 100 – 75 = 25


Difference in February = 125 – 100 = 25


Difference in March = 150 – 75 = 75


Difference in April = 125 – 125 = 0


Difference in May = 150 – 100 = 50


Difference in June = 150 – 125 = 25


C) The difference in actual and expected sales was the least, i.e. 0, in the month of April.


D) The sales of cars in Jan = 75


The sales of cars in Feb = 100


The sales of cars in March = 75


∴ The total sales of cars in the three months = 75 + 100 + 75 = 250


E) The last three months are April, May and June.


The sales of cars in April = 125


The sales of cars in May = 100


The sales of cars in June = 150


∴ The total sales of cars in the last 3 months = 125 + 100 + 150


= 375


Average = = = 125.


∴ The average sales of cars in the last three months = 125.


F) The total sales in the first three months = 250


The total sales in the last three months = 375


∴ Ratio = = =



Question 56.

The graph given below shows the marks obtained out of 10 by Sonia in two different tests. Study the graph and answer the questions that follow.



A) What information is represented by the axes?

B) In which subject did she score the highest in Test I?

C) In which subject did she score the least in Test II?

D) In which subject did she score the same marks in both the Tests?

E) What are the marks scored by her in English in Test II?

F) In which test was the performance better?

G) In which subject and which test did she score full marks?


Answer:

A) The x-axis represents the different subjects while the y-axis represents the marks obtained by Sonia in each subject.


B) In Test I, she scored the highest, i.e. 10 marks, in Maths.


C) She scored the least, i.e. 6 marks, in English and Hindi.


D) She did not score the same marks in any of the subjects in both the tests.


E) She scored 6 marks in English in Test II.


F) The total marks in Test I = 7 + 8 + 10 + 7 + 5 = 37


The total marks in Test II = 6 + 6 + 8 + 9 + 8 = 37


The performance was the same in both the tests.


G) She scored full marks, i.e. 10 marks in Maths in Test I.



Question 57.

Find the coordinates of the vertices of the given figures.



Answer:

The coordinates are starting from the left-most and moving clockwise.

For figure I, the coordinates of its vertices are (1, 1), (2, 3), (4, 2) and (3, 0).


For figure II, the coordinates of its vertices are (0, 5), (2, 4) and (1, 2).


For figure III, the coordinates of its vertices are (1, 5), (2, 6), (3, 6), (4, 5), (4, 4), (2, 4) and (2, 5).


For figure IV, the coordinates of its vertices are (4, 3), (5, 5), (6, 3) and (5, 1).



Question 58.

Study the graph given below of a person who started from his home and returned at the end of the day. Answer the questions that follow.



A) At what time did the person start from his home?

B) How much distance did he travel in the first hours of his journey?

C) What was he doing from 3 pm to 5 pm?

D) What was the total distance travelled by him throughout the day?

E) Calculate the distance covered by him in the first 8 hours of his journey.

F) At what time did he cover 16 km of his journey?

G) Calculate the average speed of the man from (a) A to B, (b) B to C, (c) At what time did he return home?


Answer:

A) The person started from his home at 10 am, since the distance is 0 km at that time. (Note :Even though the distance at 10 pm is also 0 km, it is after the journey)


B) The first part of the graph stops at the value of 20 on the y-axis after which it first becomes constant and then starts decreasing. Hence, he travelled 20 km in the first hours of his journey.


C) The graph from 3 pm to 5 pm is parallel to the x-axis. This indicates that the person did not travel any distance in those 2 hours. So, the person was at one place from 3 pm to 5 pm.


D) He travels 20 km in the first part of the day and again travels 20 km to come back to his starting point.


∴ Total distance = 20 + 20 = 40 km.


E) The first 8 hours of the journey mean from 10 am to 6 pm. He covered 20 km up to 3 pm.


He was in the same place till 5 pm. So distance covered from 3 pm to 5 pm = 0 km.


The distance at 6 pm is 16 km and at 5 pm is 20 km.


So, distance covered from 5 pm to 6 pm = 20 – 16 = 4 km.


∴ Total distance covered in the first 8 hours = 20 + 4 = 24 km.


F) He covered 16 km of his journey at 2 pm. (Note :Even though the graph shows 16 km at 6 pm, too, the distance covered at 6 pm will be 24 km.)


G)


(a). The total distance travelled from A to B = 20 – 0 = 20 km


Now, we first need to convert 3 pm into 24 hour format.


3 pm = 12 + 3 = 15 pm


The total time taken from A to B = 15 – 10 = 5 hours


∴ Average speed from A to B = = = 4 km/hr.


(b) The total distance travelled from B to C = 0 km (since the distance is constant)


The time taken from B to C = 5 pm – 3 pm = 2 hours.


∴ Average speed from B to C = = = 0 km/hr.


(c) He returned home at 10 pm since the distance becomes 0 again at 10 pm.



Question 59.

Plot a line graph for the variables p and q where p is two times q i.e, the equation is p = 2q. Then find.

A) the value of p when q = 3

B) the value of q when p = 8


Answer:

The given equation is p = 2q.


Here, p is the dependent variable and q is the independent variable.


So, p will be on the y-axis and q on the x-axis.


When q = 0,


p = 2 (0) = 0


When q = ,


p = 2 = 1


When q = 1,


p = 2 (1) = 2


When q = 2,


p = 2 (2) = 4



The points in the graph are


A = (0, 0)


B = ( , 1)


C = (1, 2)


D = (2, 4)



The line segments are



A) When q = 3,


p = 6 (from the graph)


B) When p = 8,


p = 4 (from the graph)



Question 60.

Study the graph and answer the questions that follow.



A) What information does the graph give?

B) On which day was the temperature the least?

C) On which day was the temperature 31oC?

D) Which was the hottest day?


Answer:

A) The x-axis shows the days of the week and the y-axis shows the maximum temperature.


∴The graph gives information about the maximum temperature recorded during a particular week.


B) The temperature was the least, i.e. 25°C, on Sunday.


C) The temperature was 31°C on Saturday. (Draw a line from 31, parallel to the x-axis, and find the point at which it coincides with one of the points which are plotted on the graph.)


D) The hottest day is the day with the maximum temperature. The maximum temperature is 34°C, which was recorded on Friday.


∴ Friday was the hottest day.



Question 61.

Study the distance-time graph given below for a car to travel to certain places and answer the questions that follow.



A) How far does the car travel in 2 hours?

B) How much time does the car take to reach R?

C) How long does the car take to cover 80 km?

D) How far is Q from the starting point?

E) When does the car reach the place S after starting?


Answer:

A) Find the y-coordinate when the x-coordinate is 2.


Here, when x = 2 hours, y = 80 km.


∴ The car travels 80 km in 2 hours.


B) The coordinates of the point R are (5, 200). Since the time is represented by the x-axis, the time taken by the car to reach point R is 5 hours.


C) The x-coordinate when y = 80 is 2. Thus, it takes the car 2 hours to cover 80 km.


D) The coordinates of Q are (3, 120) and those of the starting point are (0, 0). Since the y-axis represents the distance covered, the distance of point Q from the starting point = 120 – 0 = 120 km.


E) The coordinates of point S are (6, 240) and those of the starting point are (0, 0). Since time is denoted on the x-axis, the time when the car reaches S after starting = 6 – 0 = 6 hours.



Question 62.

Locate the points A (1, 2), B (4, 2) and C (1, 4) on a graph sheet taking suitable axes. Write the coordinates of the fourth point D to complete the rectangle ABCD.


Answer:

The points in the graph are


A = (1, 2)


B = (4, 2)


C = (1, 4)



The incomplete rectangle on the graph will look like



The completed rectangle ABCD on the graph is



∴ The coordinates of point D, to complete the rectangle ABCD are D (4, 4).



Question 63.

Locate the points A(1,2), B(3,4) and C(5,2) on a graph sheet taking suitable axes. Write the coordinates of the fourth point D to complete the rhombus ABCD. Measure the diagonals of this rhombus and find whether they are equal or not.


Answer:

The points on the graph are

A = (1, 2)


B = (3, 4)


C = (5, 2)



The incomplete rhombus on the graph will look like



The completed rhombus ABCD on the graph is



∴ The coordinates of point D to complete the rhombus ABCD are D (3, 0).


The diagonal AC has the y-coordinate constant, i.e. 2.


∴ The length of AC = difference in x-coordinates = 5 – 1 = 4 units


The diagonal BD has the x-coordinate constant, i.e. 3.


∴ The length of BD = difference in y-coordinates = 4 – 0 = 4 units


∴ The two diagonals of rhombus ABCD are equal in length.



Question 64.

Locate the points P (3, 4), Q (1, 0), R (0, 4), S (4, 1) on a graph sheet and write the coordinates of the point of intersection of line segments PQ and RS.


Answer:

Graph1 : plotting the points



Graph 2 : drawing the lines and finding their intersection



From the second graph , we see that N is the point of intersection of PQ and RS.


Its co-ordinates from the graph can be seen are N(2.1,2.4).



Question 65.

The graph given below compares the sales of ice creams of two vendors for a week.



Observe the graph and answer the following questions.

A) Which vendor has sold more ice creams on Friday?

B) For which day was the sales same for both the vendors?

C) On which day did the sale of vendor A increase the most as compared to the previous day?

D) On which day was the difference in sales the maximum?

E) On which two days was the sales same for vendor B?


Answer:

A) From the given graph , we can see that , on Friday vendor A sold 35 ice creams and on the same day , vendor B sold 25 ice creams. So clearly , we can say that vendor A sold more ice creams on Friday.


B) From the given graph , we can see that , on Sunday both the vendors sold 50 ice creams. So clearly , on Sunday the sale of ice creams was same for both the vendors.


C) From the given graph , we can see that , on Sunday the sale of vendor A increase the most as compared to the previous day(Saturday) ie. By 20 sales.


D) From the given graph , we can see that , on Thursday , vendor A sold 20 ice creams and vendor B sold 40. So, the difference between the sales is of 20 ice creams which is clearly the highest. ∴ we can say that, on Thursday , the difference in sales was maximum.


E) From the given graph , we can see that , on Tuesday and Wednesday ,the sale of vendor B was 30.


∴ we can say that, on Tuesday and Wednesday the sales were same for vendor B.



Question 66.

The table given below shows the temperatures recorded on a day a different times.



Observe the table and answer the following questions.

A) What is the temperature at 8 am?

B) At what time is the temperature 3oC?

C) During which hour did the temperature fall?

D) What is the change in temperature between 7 am and 10 am?

E) During which hour was there a constant temperature?


Answer:

A) From the given graph , we can see that , the temperature at 8am was 7°C.


B) From the given graph , we can see that , at 6am the was temperature 3oC.


C) From the given graph , we can see that , the fall in temperature was seen after 5am and till 6am.


D) From the given graph , we can see that , the temperature at 7am was 5°C and the temperature at 10am was 8°C , so the change in temperature between 7 am and 10 am is (8-5)°C = 3°C.


E) From the given graph , we can see that , the temperature was constant from 8am to 9am.



Question 67.

The following table gives the growth chart of a child.



Draw a line graph for the table and answer the questions that follow.



A) What is the height at the age of 5 years?

B) How much taller was the child at the age of 10 than at the age of 6?

C) Between which two consecutive periods did the child grow more faster?


Answer:

A) From the given graph , we can say that , the height at the age of 5 years is 100cm.


B) From the given graph , we can say that , the height of the child at the age of 6 years is 110cm, and the height of the child at the age of 10 years is 130cm.


∴ we can say that the child of age 10 years is taller by 20cm from the child at the age of 6 years.


C) From the given graph , we can say that , between 2 and 4 years the growth in height of the child is of 15cm and between 2 and 4 years the growth in height of the child is of 20cm , so we can say that the 2 consecutive periods between which the child grow more faster were 2-4years and 4-6 years.



Question 68.

The following is the time-distance graph of Sneha’s walking.



A) When does Sneha make the least progress? Explain your reasoning.

B) Find her average speed in km/hour.


Answer:

A) From the graph we can say that , Sneha made the least progress from the interval 25 minutes to 40 minutes.


We see that initially , she is travelling approximately 0.5km in 10min , 0.25km in 5min , till the first 25 mins. But after 25 mins, her speed decreased as she travelled 0.25km in 15min.


We can say that because of her speed in that interval i.e. = = 1km/hr which the lowest among all.


B) As we know that ,


Average speed = = = = × 60 = 2.18km/hr.


∴ Average speed = 2.18km/hr.



Question 69.

Draw a parallelogram ABCD on a graph paper with the coordinates given in Table I. Use this table to complete Tables II and III to get the coordinates of E,F,G,H, and J,K,L,M.







Draw parallelograms EFGH and JKLM on the same graph paper.


Answer:

Graph 1 : parallelogram ABCD





Graph 2 : Parallelogram EFGH and JKLM along with ABCD.




Question 70.

Plot the points (2,4) and (4,2) on a graph paper, then draw a line segment joining these two points.

Extend the line segment on both sides to meet the coordinate axes. What are the coordinates of the points where this line meets the x-axis and the y-axis?


Answer:

The two points A(2,4) and B(4,2) is drawn on the graph paper as shown below:



Let AB is a line segment which is extended from both the ends to meet the axes.



The co-ordinates of the point on y-axis , where the line segment meet will be of the form (0,y) and the co-ordinates of the point on x-axis , where the line segment meet will be of the form (x,0).


Here , in the above figure , we can see that The co-ordinates of the point on y-axis , where the line segment meet is (0,6) and the co-ordinates of the point on x-axis , where the line segment meet is (6,0).



Question 71.

The following graph shows the change in temperature of a block of ice when heated. Use the graph to answer the following questions:



A) For how many seconds did the ice block have no change in temperature?

B) For how long was there a change in temperature?

C) After how many seconds of heating did the temperature become constant at 100°C?

D) What was the temperature after 25 seconds?

E) What will be the temperature after 1.5 minutes? Justify your answer.


Answer:

A) From the given graph , we can see that ,from 0 to 20 seconds there is no change in the temperature of the block.


B) From the given graph , we can see that , the change in temperature was from 20 to 50 seconds ie. for (50-20) = 30 seconds.


C) From the given graph , we can see that, after heating for 50 seconds , the temperature became constant at 100°C.


D) From the given graph , we can see that , the temperature after 25 seconds was 20°C.


E) From the given graph , we can see that , the temperature after 50 seconds of heating remains constant at 100°C till infinite time. So we can say that the temperature after 1.5 minutes will be 100°C.



Question 72.

The following graph shows the number of people present at a certain shop at different times. Observe the graph and answer the following questions.



A) What type of a graph is this?

B) What information does the graph give?

C) What is the busiest time of day at the shop?

D) How many people enter the shop when it opens?

E) About how many people are there in the shop at 1:30 pm?


Answer:

A) The above graph is a line graph.


B) The above graph gives the information about the number of people present at a certain shop at different times.


C) From the given graph , we can see that , the busiest time of day at the shop is 1pm ie. 25 people visited the shop.


D) From the given graph , we can see that , 5 people enter the shop when it opens(at 10am).


E) From the given graph , we can see that , 20 are there in the shop at 1:30 pm.



Question 73.

A man started his journey on his journey on his car from location A and came back. The given graph shows his position at different times during the whole journey.



A) At what time did he start and end his journey?

B) What was the total duration of journey?

C) Which journey, forward or return, was of longer duration?

D) For how many hours did he not move?

E) At what time did he have the fastest speed?


Answer:

A) From the graph , we can say that, the man started his journey at 5:30 am and ended at 6pm.


B) From the graph , we can say that, the total duration of journey is hours ie. From 5:30 am to 6pm.


C) From the graph , we can say that, the forward journey was of hours and the return journey was of 4 hours.


∴ The forward journey was of longer duration.


D) From the graph , we can say that, the man did not move for 6 hours(he did not move from 6:30 am to 9:30 am and 10am to 1pm).


E) From the graph , we can say that, the man had the fastest speed from 1pm to 2pm because in that interval he covered 60kms in just 1 hour.



Question 74.

The following graph shows the journey made by two cyclists, one from town A to B and the other from town B to A.



A) At what time did cyclist II rest? How long did the cyclist rest?

B) Was cyclist II cycling faster or slower after the rest?

C) At what time did the two cyclists meet?

D) How far had cyclist II travelled when he met cyclist I?

E) When cyclist II reached town A, how far was cyclist I from town B?


Answer:

A) The horizontal axis (or the X axis) indicates the time. The vertical axis (or the Y axis) indicates the distance from the town A to B. The dotted line shows the journey of cyclist II.


∴ from the given graph, cyclist II rest at 8.45 AM to 9.00AM for 15 minutes


B) Cyclist II cycling faster after the rest because he covers the distance of 20km (from 10km to 30km) in 1hr (from 9 AM to 10 AM)


C) The two cyclists meet at 9.00AM shows in the graph


D) Cyclist II travelled from the town B to A, he travelled 20Km when he met cyclist I


E) In the given graph, the cyclist I was far from 10KM to town B when cyclist II reached town A



Question 75.

Ajita starts off from home at 07.00 hours with her father on a scooter that goes at a uniform speed of 30km/h and drops her at her school after half an hour. She stays in the school till 13 30hours and takes an auto rickshaw to return home. The rickshaw has a uniform speed of 10km/h. Draw the graph for the above situation and also determine the distance of Ajita’s school from her house.


Answer:

Given that, Ajita goes to school at a uniform speed on her father’s scooter = 30km/h


Time taken to reach her school = 30 min =


Distance between her home and school = speed × time taken to reach


=


= 15 km


∴ Distance = 15 KM




∴ Distance covered by Ajita in 1 min = 1/2 km = 500m


The graph of the above situation is as follows




Question 76.

Draw the graph using suitable scale to show the annual gross profit of a company for a period of five years.



Answer:

Let us take years on X axis and gross profit on Y axis.


The line graph is shown below for the annual gross profit of a company for a period of five years.




Question 77.

The following chart gives the growth in height in length of percentage of full height of boys and girls with their respective ages.



Draw the line graph of above data on the same sheet and answer the following questions.

A) In which year both the boys and the girls achieve their maximum height?

B) Who grows faster at puberty (14 years to 16 years of age)?


Answer:

A) Let us draw a graph as per given chart. Let the age of boys and girls in X axis and their height in Y axis.



Girls in the year 17 and boys in the year 18 achieve their maximum height.


B) Girls grow faster than the boys at puberty shown in the graph.



Question 78.

The table shows the data collected for Dhruv’s walking on a road.



A) Plot a line graph for the given data using a suitable scale.

B) In what time periods did Dhruv make the most progress?


Answer:

Let us draw a graph as per given chart. Let the time taken by dhruv walking on a road is in X axis and distance in Y axis.



B) The most progress time periods from 0 to 5 min and from 5 to 10 min were made by Dhruv.



Question 79.

Observe the given carefully and complete the table given below.





Answer:

From the given graph, let us observe the following points.


X axis is placed in horizontal and Y axis is in vertical. So,


X = 1, Y = 2.5


X = 2, Y = 5


X = 3, Y = 10


X = 4, Y = 15


∴ Fill the above observed points in the table, it is shown as follows




Question 80.

This graph shows the per cent of students who dropped out of school after completing High School. The point labelled A shows that, in 1996, about 4.7% of students dropped out.



A) In which year was the dropout the rate highest? In which year was it the lowest?

B) When did the per cent of students who dropped out of high school first fall below 5%?

C) About what per cent of students dropped out of high school in 2007? About what per cent of students stayed in high school in 2008?


Answer:

A) From the given graph, the dropout rate is highest in the year 1990 and lowest in the year 2000.


B) The percentage of students who dropped out of high school first fall below 5% is in the year is 1996


C) In 2007,4.8% of students dropped out of high school. In 2008 0.1% of students stayed in high school.



Question 81.

Observe the toothpick pattern given below:





(a) Imagine that this pattern continues. Complete the table to show the number of toothpicks in the first six terms.



(b)Make a graph by taking the pattern numbers on the horizontal axis and the number of toothpicks on the vertical axis. Make the horizontal axis from 0 to 10 and the vertical axis from 0 to 30.

(c) Use your graph to predict the number of toothpicks in patterns 7 and 8. Check your answers by actually drawing them.

(d) Would it make sense to join the points on this graph? Explain.


Answer:

(a) Let us observe the pattern given and complete the table.


Pattern and toothpicks are related as follows


1→ 4,


2→ 4 + 3 = 7


3→ 7 + 3 = 10


4→ 10 + 3 = 13


5→ 13 + 3 = 16


6→ 16 + 3 = 19


∴ fill the above details in the table. we get,



(b) The graph is plotted as the pattern numbers on the horizontal axis and the number of toothpicks on the vertical axis.



(c) The graph follows y = 3x + 1 pattern.


If x = 7 then y = (3 ×7) + 1 = 22


If x = 8 then y = (3 ×8) + 1 = 25



(d) Yes, X and Y follows the y = 3x + 1 pattern.



Question 82.

Consider this input/output table.



(a) Graph the values from the table by taking input along horizontal axis from 0 to 8 and Output along vertical axis from 0 to 24.

(b) Use your graph to predict the outputs for inputs of 3 and 8.


Answer:

(a) Let as plot the graph as per the given table. It is shown as below



This graph follows y = 3x-1 pattern.


(b) The graph follows y = 3x-1 pattern.


If x = 3 then y = (3 ×3)-1 = 5


If x = 8 then y = (3 ×8)-1 = 23




Question 83.

This graph shows a map of an island just off the coast of a continent. The point labelled B represents a major city on the coast. The distance between grid lines represents 1 km.



Point A represents a resort that is located 5 km East and 3 km North of point B. The values 5 and 3 are the coordinates of point

A. The coordinates can be given as the ordered pair (5, 3), where 5 is the horizontal coordinate and 3 is the vertical coordinate.

(i) On a copy of the map, mark the point that is 3 km East and 5 km North of Point B and label it S. Is point S in the water or on the island? Is point S in the same place as Point A?

(ii) Mark the point that is 7 km east and 5 km north of point B and label it C. Then mark the point that is 5 km east and 7 km north of point B and label it D. Are points C and D in the same place? Give the coordinates of Points C and D.

(iii) Which point is in the water, (2, 7) or (7, 2)? Mark the point which is in water on your map and label it E.

(iv) Give the coordinates of two points on the island that are exactly 2 km from Point A.

(v) Give the coordinates of the point that is halfway between Points L and P.

(vi) List three points on the island with their x-coordinates greater than 8.

(vii) List three points on the island with a y-coordinate less than 4.


Answer:

(i)


As per the given statement, point S is plotted and it is on the water. The point S is not in the same place A.


(ii) The points C and D are not in the same place. The coordinates of C is (5,7) and D is (7,5).


(iii) The point (2,7) is in the water and labelled as E.


(iv) The coordinates (7,3) and (5,5) are on the island and exactly 2 km from Point A.


(v) (8.5,3) is the coordinates of the point that is halfway between Points L and P.


(vi) (9,4),(10,4) and (11,5) are the three points on the island with their x-coordinates greater than 8.


(vii) (5,3),(6,2) and (7,2) are the three points on the island with their Y-coordinates less than 4.



Question 84.

As part of his science project, Prithvi was supposed to record the temperature every hour one Saturday from 6 am to midnight. At noon, he was taking lunch and forgot again. He recorded the data so collected on a graph sheet as shown below.



A) Why does it make sense to connect the points in this situation?

B) Describe the overall trend, or pattern, in the way the temperature changes over the time period shown on the graph.

C) Estimate the temperature at noon and 8 pm.


Answer:

A) To observe change in the data over a period of time, we plot a graph and join the points.


B) We can see from the graph that temperature increases from 8°C at 6 am to 21°C at 1 pm (between 12 noon and 2 pm, we can say that temperature is approximately 21°C) and then it decreases to around 9°C at 9 pm(between 8 pm and 10 pm in the graph). It remains constant for an hour (9 pm to 10 pm) and then decreases. We observe that at 12 pm the temperature is 8°C, same as it was at 6 am. Thus, we see that temperature first increases and then decreases from 6 am to 12 pm.


C) On looking carefully at the graph, we see that temperature is around 17°C at 11 am and thus, it is 19°C at 12 noon.


At 8 pm temperature is 10°C.



Question 85.

The graph given below compares the price (in Rs) and weight of 6 bags (in kg) of sugar of different brands A, B, C D, E, F.



A) Which brand(s) costs/cost more than Brand D?

B) Bag of which brand of sugar is the heaviest?

C) Which brands weigh the same?

D) Which brands are heavier than brand B?

E) Which bag is the lightest?

F) Which bags are of the same price?


Answer:

A) Brands which cost more than Brand D are:


a. Brand F


b. Brand E


B) Bag of Brand D is the heaviest.


C) On looking closely we see that brands which weigh the same are Brand C and Brand E.


D) Brands heavier than brand B are:


i. Brand E


ii. Brand C


iii. Brand D


E) Bag of brand A is the lightest


F) On looking closely we see that brands with the same price are Brand C and Brand A.



Question 86.

The points on the graph below represent the height and weight of the donkey, dog, crocodile, and ostrich shown in the drawing.



A) What are the two variables represented in the graph?

B) Which point represents each animals? Explain.


Answer:

A) The two variables represented in the graph are Weight and Height.


B) Point D represents Ostrich because it is tallest among donkey, dog, crocodile.


Point B represents Donkey as after Ostrich it is second tallest among the group.


Point A is for Crocodile as it smallest among all the given animals.


Point C represents Dog.



Question 87.

The two graphs below compare Car A and Car B. The left graph shows the relationship between age and value. The right graph shows the relationship between size and maximum speed.





Use the graphs to determine whether each statement is true or false, and explain your answer.

A) The older car is less valuable.

B) The faster car is larger.

C) The larger car is older.

D) The faster car is older.

E) The more valuable car is slower.


Answer:

A) False


From the graph, we can see that the value of car increases with the increase in the age of car. Thus, older car is more valuable. Hence, the given statement is false.


B) True


We observe from the graph that speed increases with the size of the car. Thus, the given statement is true.


C) True


We can see that B is both the larger and older car from the graphs


D) True


We can see that B is both the faster and older car from the graphs


E) False


B which is more valuable than A is also faster than A.



Question 88.

Sonal and Anmol made a sequence of tile designs from square white tiles surrounding one square purple tile. The purple tiles come in many sizes. Three of the designs are shown below.

A) Copy and complete the table





B) Draw a graph using the first five pairs of numbers in your table.

C) Do the points lie on a line?


Answer:

A)



B)



C) No, the points do not lie on the same line.



Question 89.

Sonal and Anmol then made another sequence of the designs. Three of the designs are shown below.



A) Complete the table



B) Draw a graph of rows and number of white tiles. Draw another graph of the number of rows and the number of purple tiles. Put the number of rows on the horizontal axis.

C) Which graph is linear?


Answer:

A)



B)


C)


D) Neither of the graph is linear



Question 90.

Create a table like the one shown



If an estimate is the same as the actual measurement then the point (actual measurement, estimate) lies on the line, straight line p. For example, if an object measures 5 cm and you estimate it to 5 cm, then the graph of its point lies on line p in the figure below.



Using your completed table,

A. Plot the data from the table where the coordinates of the points are (measurement, estimate).

B. Identify the objects overestimated.

C. Identify the objects underestimated.

D. By looking at the graph, how can overestimates and underestimates be determined? How accurate is your estimation?


Answer:


A.



B.


Overestimated objects are:


a) EraserZ


b) Palm


c) Geometry box


C.


Underestimated objects are:


a) Math Notebook


D.


When the estimated measurements are more than actual measurements, then it can be said we have Overestimated our data.


When the estimated measurements are less than actual measurements, then it can be said we have Underestimated our data.


We able to determine only one observation accurately, that is, length of a pen.