SOLUTION: A swimming pool holds 540,000 liters of water. THe pool has two drainage pipes. When the pool is completely full, the first pipe alone can empty it in 180 min, and the second pipe

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A swimming pool holds 540,000 liters of water. THe pool has two drainage pipes. When the pool is completely full, the first pipe alone can empty it in 180 min, and the second pipe       Log On


   

Question 439419: A swimming pool holds 540,000 liters of water. THe pool has two drainage pipes. When the pool is completely full, the first pipe alone can empty it in 180 min, and the second pipe alone can empty it in 120 min. When both pipes are draining together, how long does it take them to empty the pool?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Pipe A 3 hours
It does 1/ 3 of the job in 1 hour
Pipe B 2 hours
It does 1/ 2 of thejob in 1 hour
Together they will do 1/ 3 + 1/ 2
Together they will do 5/ 6 of the job in one hour
So they will take 1 1/5 hours
So they will take 1.2 hours = 72 minutes