Two pipes, X and Y, can fill a tank in 12 minutes and 18 minutes, respectively. If both the pipes are opened simultaneously, how long will it take to fill the tank?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 7minutes.
X's rate = 1/12 and Y's rate = 1/18
Combined rate = 1/12 + 1/8 = 5/36
Time = 36/5 = minutes