Two students A and B contributed ₹ 100 towards the Prime Minister's Relief Fund to help the earthquake victims

Let the contribution of A and B be ₹ x and ₹ y, respectively.

Total contribution of A and B = ₹ x + ₹ y = ₹ (x + y)

It is given that the total contribution of A and B is ₹ 100.

∴ x + y = 100

This is the linear equation satisfying the the given data.

x + y = 100 

⇒ y = 100 – x

When x = 10, y = 100 – 10 = 90

When x = 40, y = 100 – 40 = 60

When x = 60, y = 100 – 60 = 40

Thus, the points on the line x + y = 100  are as given in the following table:

Plotting the points (10, 90), (40, 60) and (60, 40) and drawing a line passing through these points, we obtain the graph of of the line x + y = 100.