A tank has a leak that can drain it completely in 20 minutes. When a tap supplying water at 4 liters per minute is opened, the tank takes 24 minutes to empty. What is the total capacity of the tank in liters?

Explanation

Let the tank's capacity be x liters. The leak empties the tank in 20 minutes, so the leak's rate is x/20 liters per minute. The tap adds water at 4 liters per minute. When both operate together, the tank empties in 24 minutes, so the net emptying rate is x/24 liters per minute. Setting up the equation: (x/20) - 4 = x/24. Solving for x gives x = 480 liters.