Question

Two pipes a and b can fill a tank in 9 hours and 3 hours respectively. if they are opened on alternate hours and if pipe a is opened first, in how many hours will the tank be full?

Answer 1

9 X 3 / 12 = 9/4

1/9 + 1/3 = 4/9 will fill in 2 hours.

Remain 1 - 4/9 =5/9

Another 4/9 in 2 hour, total 4 hour...

Remain 1/9 it will be fill by A in 1 hour


Total hour 2+2+1=5 hour