Two taps can fill a tub in 6 minutes and 4 minutes, respectively. A pipe can empty it in 3 minutes. If all three are kept open simultaneously, when will the tub be full?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 12 min.
Tap A's rate = 1/6 per min
Tap B's rate = 1/4 per min
Empty pipe's rate = 1/3 per min
Net rate = 1/6 + 1/4 – 1/3 = 1/12 per min
Time to fill = 12 minutes