A drum of kerosene is 3/4 full. When 30 liters of kerosene is drawn from it, it remains 712 full. The capacity of the drums is = ?

Answer: Option D

Let the capacity of the drum be x liters
Then,
$$\begin{array}{rl}& \frac{3}{4}x-\frac{7}{12}x=30\\ & \iff 9x-7x=12\times 30\\ & \iff 2x=360\\ & \iff x=180\end{array}$$