Exercise 15.1 Exercise 15.2 Exercise 15.3
Exercise 15.3
Question 1
Draw the graphs for the following tables of values, with suitable scales on the axes.
(a) Cost of apples

Number of apples
1
2
3
4
5
Cost (in Rs)
5
10
15
20
25
(b) Distance travelled by a car

Time (in hours)
6 a.m.
7 a.m.
8 a.m.
9 a.m.
Distance (in km)
40
80
120
160
(i) How much distance did the car cover during the period 7.30 a.m. to 8 a.m.?
(ii) What was the time when the car had covered a distance of 100 km since its start?
(c) Interest on deposits for a year:

Deposit (in Rs)
1000
2000
3000
4000
5000
Simple interest (in Rs)
80
160
240
320
400
(i) Does the graph pass through the origin?
(ii) Use the graph to find the interest on Rs 2500 for a year:
(iii) To get an interest of Rs 280 per year, how much money should be deposited?
Sol :
(a) Taking a suitable scale (for xaxis, 1 unit = 1 apple and for yaxis, 1 unit = Rs 5), we can mark the number of apples on xaxis and the cost of apples on yaxis. A graph of the given data is as follows.
(b) Taking a suitable scale (for xaxis, 2 units = 1 hour and for yaxis, 2 units = 40 km), we can represent the time on xaxis and the distance covered by the car on yaxis. A graph of the given data is as follows.
(i) During the period 7:30 a.m. to 8 a.m., the car covered a distance of 20 km.
(ii) The car covered a distance of 100 km at 7:30 a.m. since its start.
(c) Taking a suitable scale,
For xaxis, 1 unit = Rs 1000 and for yaxis, 1 unit = Rs 80
We can represent the deposit on xaxis and the interest earned on that deposit on yaxis. A graph of the given data is obtained as follows.
From the graph, the following points can be observed.
(i) Yes. The graph passes through the origin.
(ii) The interest earned in a year on a deposit of Rs 2500 is Rs 200.
(iii) To get an interest of Rs 280 per year, Rs 3500 should be deposited.
Question 2
Draw a graph for the following.
(i)

Side of square (in cm)
2
3
3.5
5
6
Perimeter (in cm)
8
12
14
20
24
Is it a linear graph?
(ii)

Side of square (in cm)
2
3
4
5
6
Area (in cm^{2})
4
9
16
25
36
Is it a linear graph?
Sol :
(i) Choosing a suitable scale,
For xaxis, 1 unit = 1 cm and for yaxis, 1 unit = 4 cm
We can represent the side of a square on xaxis and the perimeter of that square on yaxis. A graph of the given data is drawn as follows.
It is a linear graph.
(ii)Choosing a suitable scale,
For xaxis, 1 unit = 1 cm and for yaxis, 1 unit = 4 cm^{2}
We can represent the side of a square on the xaxis and the area of that square on yaxis. A graph of the given data is as follows.
It is not a linear graph.