SOLUTION: One pipe can fill a swimming pool in 6 hours, and another pipe can do it in 9 hr. How long will it take the two pipes working together to fill the pool 3/4 full?

Question 409722: One pipe can fill a swimming pool in 6 hours, and another pipe can do it in 9 hr. How long will it take the two pipes working together to fill the pool 3/4 full?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = time for both pipes to fill 3/4 of the pool
given:
1 pool/6 hours
1 pool/9 hours
---------------------

Multiply both sides by

hr
The 2 pipes together take 2.7 hr, or 2 hrs and 42 min
to fill 3/4 of the pool

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