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So, we get a table of values as follows:

Sum (in `) 1000 2000 3000 5000 7000

Annual S.I. (in `) 100 200 300 500 700
Now,

• Select a scale, on horizontal axis, 1 unit = `1000, and on vertical axis, 1 unit = `100.
• Mark principal along horizontal axis and simple interest along vertical axis.
• Plot the points (1000, 100), (2000, 200), (3000, 300), … , (7000, 700).

• Join the points and obtain the graph as shown below.
(a) Corresponding to an investment
of `2500 on the x-axis, we locate Y Scale: On x-axis, 1 unit = `1000
a point 2500 on the x-axis and 800 On y-axis, 1 unit = `100
draw a vertical line through it 700
to meet the graph at P. From (7000, 700)
P, draw a horizontal line that 600 Q
)
meets the y-axis at 250.
So, the annual interest on an 500 (5000, 500)
investment of `2500 is `250. 400

(b) Corresponding to an annual Annual Simple Interest (in ` 300 (3000, 300)
interest of `600 on the y-axis, 250 P
we locate the point on the y-axis 200 (2000, 200)
and draw a horizontal line
through it to meet the graph at 100 (1000, 100)
point Q. From Q, draw a vertical X
line that meets the x-axis at O(0, 0) 1000 2000 2500 3000 4000 5000 6000 7000 8000
6000. Sum (in `)
So, a person has to make an
investment of `6000 to get an annual interest of `600.
Example 11: (Time and Distance)
Rohit can drive a car at a uniform speed of 40 km/h. Draw a time-distance graph for this situation.
Using the graph drawn, find

(a) the time taken by Rohit to drive 60 km.
1
(b) the distance covered by Rohit in 3 hours .
2
Solution: Consider the hours of drive as 1 hour, 2 hours, 3 hours, 5 hours, then the distance covered
can be calculated as below:
Remember
Hours of drive Distance covered (in km)
1 hour 40 km S = D
T
2 hours (2 × 40) km = 80 km where, S = speed
3 hours (3 × 40) km = 120 km D = distance
5 hours (5 × 40) km = 200 km T = time taken

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