Pipe A can fill a tank in 6 hours, pipe B in 4 hours, and pipe C in 12 hours. If all the pipes are open, in how many hours will the tank be filled?
Answers
A) 1.5
B) 2
C) 2.5
D) 3
E) 3.5
The part filled by A + B + C in 1 hour   = 1/6 + 1/4 + 1/12   = 12/24 = 1/2   All the three pipes together will fill the tank in 2 hours.   The answer is 2.
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Pipe A can fill a tank in 6 hours, pipe B in 4 hours, and pipe C in 12 hours. If all the pipes are open, in how many hours will the tank be filled?