An electric pump can fill a tank in 5 hours. Because of a leak in the tank, it took 10hours to fill the tank. If the tank is full, how much time will the leak take to empty it?  Choose one.
A) 10hours B) 12hours C) 8hours D) 5hours E) 15hours
Work done by the leak in 1 hour = 1/5 - 1/10 = 1/10   The leak will empty the tank in 10hours   10hoursnswer is 10hours
<result>A</result>
An electric pump can fill a tank in 5 hours. Because of a leak in the tank, it took 10hours to fill the tank. If the tank is full, how much time will the leak take to empty it?