SOLUTION: A certain swimming pool can be drained in 5 hours using a large pump. The same swimming pool can be drained in 12 hours using a small pump. How long, rounded to the nearest hour, w

Question 470039: A certain swimming pool can be drained in 5 hours using a large pump. The same swimming pool can be drained in 12 hours using a small pump. How long, rounded to the nearest hour, will it take to drain the swimming pool using 2 small pumps and 1 large pump?
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
The large pump drains 1/5 per hour.
Each small pump drains 1/12 per hour.
Together, they do 1/5 + 1/12 + 1/12 per hour
= 11/30 per hour
--> 30/11 hours
--> ~3 hours
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