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 correct choice from the following options.
A) 3 9/17 hours	B) 1 13 /17 hours	C) 2 8/11 hours	D) 4 1/ 2 hours	E) 5 1/ 2 hours
Explanation:   Pipes A and B can fill the tank in 5 and 6 hours respectively. Therefore,   part filled by pipe A in 1 hour =1/5   part filled by pipe B in 1 hour = 1/6   Pipe C can empty the tank in 12 hours. Therefore,   part emptied by pipe C in 1 hour =1/12   Net part filled by Pipes A,B,C together in 1 hour   =1/5+1/6-1/12=17/60   i.e., the tank can be filled in 60/17=3 9/17 hours.   3 9/17 hoursnswer: Option 3 9/17 hours
<result>A</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: