Two pipes A and B can fill a tank in 12 minutes and 24 minutes, respectively, while a third pipe C can empty the full tank in 32 minutes. All the three pipes are opened simultaneously. How-ever, pipe C is closed 2 minutes before the tank is filled. In how much time (in minutes) will the tank be full?

Answer: Option B

Solution

Answer: Option B

Solution:

If pipe C continues for 2 more minutes, then = 2 × (-3) = -6 litre less fill
Then, 96 - 6 = 90 litre filled
A + B - C, 1 minute = 8 + 4 - 3 = 9
Time of A + B - C = $$\frac{90}{9}$$ = 10 minutes