Question

A porter carries a load of 20 kg on his head and walks on a levelled road up to 100 m. What is the work done by the gravitational force ?

Answer 1

Complete the following table considering that the cost of apples and their number are in direct variation.

Number of apples (x) 1 4 ... 12 ...

Cost of apples (y) 8 32 56 ... 160

ANSWER:

It is given that the cost of apples (y) and number of apples (x) are in direct variation.

∴y∝x⇒y=kx, where k is constant of variation

When x = 1, y = 8.

∴ 8 = k × 1

⇒ k = 8

So, the equation of variation is

y = 8x

When y = 56,

56 = 8x

⇒ x = 7

When x = 12,

y = 8 × 12 = 96

When y = 160,

160 = 8x

⇒ x = 20

The complete is given below.

Number of apples (x) 1 4 7 12 20

Cost of apples (y) 8 32 56 96 160