Two pipes A and B can fill a tank in 40 and 120 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank? Select the correct option.
A) 30
B) 35
C) 25
D) 82
E) 22
Part filled by A in 1 min. = 1/40   Part filled by B in 1 min. = 1/120   part filled by (A + B) in 1 min. = 1/40 + 1/120 = 1/30.   Both the pipes can fill the tank in 30 minutes.   30nswer: 30
<result>A</result>
Two pipes A and B can fill a tank in 40 and 120 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?