Pipe A can fill a tank in 3 hours, pipe B in 15 hours and pipe C in 24 hours. If all the pipes are open, in how many hours will the tank be filled ?	Select
A) 2.5 hours	B) 2 hours	C) 3.5 hours	D) 3 hours	E) None of these
Explanation:   Part filled by A in 1 hour = 1/3   Part filled by B in 1 hour = 1/15   Part filled by C in 1 hour = 1/24   Part filled by (A+B+C) in 1 hour =   1/3+1/15+1/24=93/120   So all pipes will fill the tank in 1.3 hours.   Option None of these
<result>E</result>
Pipe A can fill a tank in 3 hours, pipe B in 15 hours and pipe C in 24 hours. If all the pipes are open, in how many hours will the tank be filled ?