A leak in the bottom of a tank can empty the whole tank in 8 hours. An inlet pipe fills water are the rate of 6 liters a minute. When the tank is full, the inlet is opened, and due to the leak, the tank is empty in 12 hours. How many liters does the tank hold?

Question: A leak in the bottom of a tank can empty the whole tank in 8 hours. An inlet pipe fills water are the rate of 6 liters a minute. When the tank is full, the inlet is opened, and due to the leak, the tank is empty in 12 hours. How many liters does the tank hold?

Solution:
Work done by the inlet pipe in 1 hour = (1/8 - 1/12) = (3 - 2)/24 = 1/24
Work done by the inlet pipe in 1 minute = (1/24 × 1/60) = 1/1440

Volume of 1/1440 part = 6 liters
Volume of the whole tank = (1440 × 6) = 8640 liters