Question

A drum of petrol is 3/4 full . when 30 litres is drawn from it , it is 7/12 , find the capacity of the drum.

Answer 1

The drum capacity is 180 liters.

Explanation:

Let the capacity of the drum be c. Then the contents of the drum at the beginning are (3/4)c, and

if 30 liters are drawn out, then the contents are (3/4)c - 30 liters = (7/12)c.

Here the LCD is 12, and so we have (9/12)c - (7/12)c = 30 liters, or

(2/12)c = 30 liters, or c = (12/2)(30 liters) = 180 liters

The drum capacity is 180 liters.

Answer 2

The capacity of the drum is 180 liters

Explanation:

3/4x - 30 = 7/12x

3/4x - 7/12x = 30

9/12x - 7/12x = 30

2/12x = 30

1/6x = 30

x = 30*6

x = 180 liters