An electric pump can fill a tank in 7 hours. Because of a leak in the tank, it took 14hours to fill the tank. If the tank is full, how much time will the leak take to empty it?  Choose the correct choice from the following choices
A) 10 hours B) 12 hours C) 8 hours D) 5 hours E) 14 hours

Rationale: "work done by the leak in 1 hour = 1 / 7 - 1 / 14 = 1 / 14 the leak will empty the tank in 14 hours answer is e"
Answer: E