At a constant Rate of flow, it takes 120 minutes to fill a swimming pool if a large hose is used and 180 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 most appropriate option
A) 52  B) 54  C) 56  D) 58  E) 72
time taken to fill the pool by Large Hose =120 minutes =L or 1/L=1/120 similarly 1/S=1/180   simultaneously it will take 1/L+1/S=1/120+1/180=5/360=72 minutes   Answer : 72
<result>E</result>
At a constant Rate of flow, it takes 120 minutes to fill a swimming pool if a large hose is used and 180 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?