Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank ?  Choose the correct choice from the following answers:  A) 12 min  B) 15 min  C) 25 min  D) 50 min  E) 55 min
Part filled by A in 1 min = 1/20   Part filled by B in 1 min = 1/30   Part filled by (A + B) in 1 min =(1/20 + 1/30) = 1/12   so Both pipes can fill the tank in 12 minutes.   12 minNSWER:12 min
<result>A</result>
Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank ?