Answer: (D) 7200 litres
Explanation: The capacity of tank = x litre (suppose)
Quantity of water emptied by the leak = (x/10) litres
Quantity of water admitted to the tank = (4 * 60) = 240 litre/hour
According to the question, (x/10) -(x/15) = 240
Therefore, x = 7200 litres