Tank and Cistern

There is a leak at the bottom of a tank. The leak can empty a full tank in 6 hours. A inlet pipe to the tank fills the tank at 4Litres/min. When the tank is full, the inlet pipe is opened, but due to the leak the tank is emptied out in 8 hours. What is the capacity of the tank?

Ans:

Volume of water added to the tank in 8 hours = 4 x 60 x 8 = 1920 Litres.

Volume of  extra water removed  during the additional 2 hours

= 1920 litres.

So, water removed in 6 hours = (1920/2) x 6 = 5760 litres.

So, volume of tank = 5760 litres.