Let x hours be the time taken by tap to fill the tank, then 2x hours will be the time taken by leakage to empty the tank. In 1 hour the part filled when both are opened =
1
x
−
1
2x
=
1
2x
Hence, the tank will be filled in 2x hours when both are opened. Now, 2x – x = 36 ∴ x = 36 hrs. Hence, tap alone will fill the tank in 36 hours.