Description for Correct answer:
In 1 hour, the pipe will fill \( \Large \frac{1}{8} \)th of the tank.

On account of leak in 1 hour it is able to fill only \( \Large \frac{1}{10} \)th of the tank

\( \Large \frac{1}{A}-\frac{1}{B}=\frac{1}{10}\ or\ \frac{1}{8}-\frac{1}{B}=\frac{1}{10}\ or\ B = 40 Hr. \)

Therefore, the leak at the bottom will take 40 hrs to empty the tank.