A pump can fill a tank with a water in 2 hours. Because of a leak, it took 3 hours to fill the tank. The leak can drain all the water of the full tank in how many hours?
Options
A) 2	B) 3	C) 4	D) 5	E) 6

Rationale: the rate of the pump + leak = 1 / 3 1 / 2 - leak ' s rate = 1 / 3 leak ' s rate = 1 / 2 - 1 / 3 = 1 / 6 the leak will empty the tank in 6 hours . the answer is e .
Answer: E