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.

The capacity of the drum is 180 liters

Step-by-step 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

The drum capacity is 180 liters.

Step-by-step 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.