A pipe can fill a tank in 6 hours , due to a leak in the tank it gets filled in7 hours. When the tank is full how much time will it take to empty the tank?
tank filling rate = 1/6
time taken with leakage = 1/7
new tank filling rate = 1/7
therefore, rate of leakage = 1/6 - 1/7 = (7 - 6)/42 = 1/42
hence, it will take 42 hours to empty the tank, if the tank is full.