Pipe A can fill a tank in 2 hr, pipe B in 4hr and pipe C in 8hr. If all the pipes are open in how many hours will tank be filled?	Choose the correct choice from the following answers.
A) 1hr 27min B) 2hr 19min C) 3hr 14min D) 3hr E) 5hr 45min
Part filled by (1hr 27min+B+C) in 1hour = 1/2 + 1/4 + 1/8 = 7/8   1hr 27minll the 3 pipes together will fill the tank in 1hour 27min   1hr 27minnswer is 1hr 27min
<result>A</result>
Pipe A can fill a tank in 2 hr, pipe B in 4hr and pipe C in 8hr. If all the pipes are open in how many hours will tank be filled?