Pipe A can fill a tank in 15 hours, pipe B in 30 hours and pipe C in 40 hours. If all the pipes are open, in how many hours will the tank be filled? Options
A) 2	B) 2.5	C) 3	D) 8	E) None
Sol.   Part filled by (A + B + C) in 1 hour = (1/15 + 1/30 + 1/40) = 1/8.   âˆ´ All the three pipes together will fill the tank in 8 hours.   Answer 8
<result>D</result>
Pipe A can fill a tank in 15 hours, pipe B in 30 hours and pipe C in 40 hours. If all the pipes are open, in how many hours will the tank be filled?