A pump can fill a tank with water in 10 hours. Because of a leak, it took 20 hours to fill the tank. The leak can drain all the water in ? Choose the correct choice:  A) 20hr  B) 10hr  C) 30hr  D) 14hr  E) 16hr
Work done by the leak in 1 hour = 1/10 - 1/20 = 1/20   Leak will empty the tank in 20 hours   20hrnswer is 20hr
<result>A</result>
A pump can fill a tank with water in 10 hours. Because of a leak, it took 20 hours to fill the tank. The leak can drain all the water in ?