A pipe A can fill the tank in 6 hrs. and pipe B can fill it 12 hours. But due to the leakage, tank took 30 minutes more than the usual time. If the tank is full, how long will it take for leakage alone to empty the tank.

Correct Answer: 36 hours

(A+B) can fill in one hour (1/6+1/12) part

= 2+1/12=3/12=1/4

In 4 hrs. (A+B) can fill the tank.

But due to the leakage time taken to fill the tank is 4 1/2hours, i.e. 9/2hours

In one hour (A+B) + leak can fill 2/9 part

In one hour leak pipe can empty 1/4−2/9=1/36

The leak pipe can empty the tank in 36 hrs.