SOLUTION: A new type of pump can drain a certain pool in 3 hours. An older pump can drain the pool in 6 hours. How long will it take both pumps working together to drain the pool?

Question 940496: A new type of pump can drain a certain pool in
3
hours. An older pump can drain the pool in
6
hours. How long will it take both pumps working together to drain the pool?
Found 2 solutions by ptaylor, macston:
Answer by ptaylor(2198) (Show Source): You can put this solution on YOUR website!
Let x=amount of time needed to drain the pool when both pumps are operating together
Both pumps working together drains at the rate of 1/x pool per hour
New pump drains at the rate of 1/3 pool per hour
Old pump drains at the rate of 1/6 pool per hour
Sooooo
1/3+1/6=1/x. multiply each term by 6x
2x+x=6
3x=6
x=2 hours
CK
In 2 hrs, new pump drains (1/3)*2=2/3 of the pool
In 2 hrs, old pump drains (1/6)*2=1/3 of the pool
Hope this helps----ptaylor
Answer by macston(5194) (Show Source): You can put this solution on YOUR website!
The new pump drains the pool at a rate of per hour.
the old pump drains the pool at a rate of per hour.
Together they drain at of the pool per hour.
Thus together it will take them two hours to drain the pool.
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