A drum of kerosene oil is 3/4 full. When 15 litres of oil is drawn from it, it is 7/12 full. The capacity of the drum is ........
Let Capacity of drum = a litres
A/Q,
(3/4 x a) - 15 = 7/12 x a
3a/4 - 7a/12 = 15
(3a-7a)/12 = 15
2a/12 = 15
a = 15 x 12/2
a = 90 litres
Capacity of drum = 90 litres.