Pipe ‘A’ can fill a tank in 30 hours whereas leak

Solution

Let the capacity of the tank be 90 litres {LCM (30 and 45)} Efficiency of pipe ‘A’ = 90 ÷ 30 = 3 litres/hour Efficiency of leak ‘A’ = 90 ÷ 45 = 2 litres/hour Combined efficiency of pipe ‘A’ and leak ‘A’ = 3 – 2 = 1 litre/hour Combined efficiency of pipe ‘A’, ‘B’ and leak ‘A’ = 90 ÷ 20 = 4.5 units/hour Efficiency of pipe ‘B’ = 4.5 – 1 = 3.5 units/hour Time taken by pipe ‘B’ and leak ‘A’ to fill the tank = 90 ÷ (3.5 – 2) = 60 hours