Pipes A and B can fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in?  Choose the most appropriate option
A) 3 9/19 hrs B) 3 9/77 hrs C) 3 9/17 hrs D) 3 9/57 hrs E) 3 9/27 hrs
Net part filled in 1 hour = 1/5 + 1/6 - 1/12 = 17/60   The tank will be full in 60/17 hrs, i.e., 3 9/17 hrs.Answer: 3 9/17 hrs
<result>C</result>
Pipes A and B can fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in?