Pipes A and B can fill a tank in 2 and 3 hours. Pipe C can empty it in 15 hours. If all pipes are opened together, then the tank will be filled in?
Answers
A) 60/17 hr
B) 13/12 hr
C) 42/11 hr
D) 6 hr
E) 30/23 hr
Net part filled in 1 hour = 1/2 + 1/3 - 1/15 = 23/30   The tank will be full in 30/23 hr   Answer is 30/23 hr
<result>E</result>
Pipes A and B can fill a tank in 2 and 3 hours. Pipe C can empty it in 15 hours. If all pipes are opened together, then the tank will be filled in?