Two pipes can fill a tank in 15 hours and 30 hours. While the 3rd pipe empties the full tank in 45hours. If all the 3 pipes are open in how much time will the tank be filled? Choose the correct choice from the following choices
A) 15/72
B) 88/12
C) 75/16
D) 90/11
E) 57/10
Net part filled in 1 hour = 1/15 + 1/30 - 1/45 = 11/90   The tank will be full in 90/11 hr   Answer is 90/11
<result>D</result>
Two pipes can fill a tank in 15 hours and 30 hours. While the 3rd pipe empties the full tank in 45hours. If all the 3 pipes are open in how much time will the tank be filled?