If the time taken by pipe A is 9 hours more than time taken by A + B together and pipe B takes 36 hours more than the time taken by A + B together, then find the time taken by pipe B to fill the tank.

54 h

Time taken by A+B = \(\sqrt {9 × 36}\)

                             = \(\sqrt {324}\) = 18

Time taken by B = 18  + 36 = 54 hours