Two pipes A and B can fill a tank in 24 hours and 36 hours respectively. If both the pipes are opened simultaneously, how much time will be taken to fill the tank?	Options:
A) 20 hours
B) 15 hours
C) 14 2/5 hours
D) 12 hours
E) 8 hours
Part filled by A in 1 hour = 1/24   Part filled by B in 1 hour = 1/36   Part filled by (A+B) in 1 hour = 1/24 + 1/36 = 5/72   Both the pipes together fill the tank in 72/5 = 14 2/5 hours   Answer is 14 2/5 hours
<result>C</result>
Two pipes A and B can fill a tank in 24 hours and 36 hours respectively. If both the pipes are opened simultaneously, how much time will be taken to fill the tank?