Three pipes – A, B, and C – are attached to a tank. Pipe A alone can fill the empty tank in 6 hours, pipe B alone can empty the full tank in 8 hours and pipe C alone can fill the empty tank in 12 hours. At 9 am pipe A is opened. One hour after that pipe B is opened and one hour from that pipe C is opened. At what time the tank will be full?

A. 11:40 am
B. 12:27 pm
C. 1:40 pm
D. 5 pm
E. 5:20 pm


OA E

Source: e-GMAT