2017 · Q79
Two pipes A and B can fill a tank in 12 minutes and 16 minutes respectively. If both the pipes are opened together, then after how much time, B should be closed so that the tank is full in 9 minutes?
general-mental-abilityquantitative-aptitude
- A3 min
- B4 min
- C44 min
- D43 min
Explanation
Pipe A fills 1/12 of the tank per minute, so in 9 minutes it fills 9/12 = 3/4 of the tank. Pipe B, which fills 1/16 per minute, must supply the remaining 1/4, needing 4 minutes. Hence (B).