At a constant Rate of flow, it takes 60 minutes to fill a swimming pool if a large hose is used and 90 minutes if a small hose is Used. At these constant rates, how many minutes will it take to fill the pool when both hoses are used simultaneously?	Choose the correct choice from the following answers:  A) 20  B) 25  C) 28  D) 36  E) 33
time taken to fill the pool by Large Hose =30 minutes =L or 1/L=1/60 similarly 1/S=1/90   simultaneously it will take 1/L+1/S=1/60+1/90=5/180=36 minutes   Answer : 36
<result>D</result>
At a constant Rate of flow, it takes 60 minutes to fill a swimming pool if a large hose is used and 90 minutes if a small hose is Used. At these constant rates, how many minutes will it take to fill the pool when both hoses are used simultaneously?