Pipe A can fill a tank in 20 hrs and pipe B can fill it in 60 hrs. If both the pipes are opened in the empty tank. In how many hours will it be fill quarter of that tank? Choose the correct choice from the following choices.
A) 3 hr 15 mins B) 3 hr 25 mins C) 3 hr 35 mins D) 3 hr 45 mins E) 3 hr 55 mins
Part filled A in 1 hr= (1/20)   Part filled B in 1 hr= (1/60)   Part filled by (A+B) together in 1 hr=(1/20)+(1/60)=1/15   So, The tank will be full in 15 hrs   Time taken to fill Exact quarter tank = (15) * (1/4) = 3.45 hr= 3 hr 45 mins   Answer : 3 hr 45 mins
<result>D</result>
Pipe A can fill a tank in 20 hrs and pipe B can fill it in 60 hrs. If both the pipes are opened in the empty tank. In how many hours will it be fill quarter of that tank?