SOLUTION: One pump can empty a pool in 5 days, whereas a second pump can empty the pool in 7 days. How long will it take the two pumps, working together, to empty the pool?

Question 428523: One pump can empty a pool in 5 days, whereas a second pump can empty the pool in 7 days. How long will it take the two pumps, working together, to empty the pool?

Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Emptying the tank is one job
one pipe drains in 5 days
It does 1/ 5 of the job in 1 day
other pipe 7 day
It does 1/ 7 of thejob in 1 day
Together they will do 1/5+ 1/ 7
Together they will do 12/35 of the job in one day
So they will take 2 8/9 days
So they will take 2.92 days

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