Pipes A and B can fill a tank in 5 and 6 hours. Pipe C can empty it in 12 hours. If all pipes are opened together, then the tank will be filled in? Choose the correct option.
A) 60/17 hr  B) 13/12 hr  C) 52/11 hr  D) 6 hr  E) 63/19 hr
Net part filled in 1 hour = 1/5 + 1/6 - 1/12 = 17/60   The tank will be full in 60/17 hr   60/17 hrnswer is 60/17 hr
<result>A</result>
Pipes A and B can fill a tank in 5 and 6 hours. Pipe C can empty it in 12 hours. If all pipes are opened together, then the tank will be filled in?