A pump can fill a tank with water in 5 hours. Because of a leak, it took 7 hours to fill the tank. The leak can drain all the water in ?	Choose the correct choice from the following.
A) 15hr 10min
B) 16hr 20min
C) 17hr 30min
D) 15hr
E) 14hr 25min
Work done by the leak in 1 hour = 1/5 - 1/7 = 2/35   Leak will empty the tank in 35/2 hrs = 17hr 30min   Answer is 17hr 30min
<result>C</result>
A pump can fill a tank with water in 5 hours. Because of a leak, it took 7 hours to fill the tank. The leak can drain all the water in ?