SOLUTION: One pipe fills a pool in 4 hours. A second pipe, used to drain the water from the pool, can empty the pool in 8 hours. The owner of the pool mistakenly opened both pipes. How lo

Question 923219: One pipe fills a pool in 4 hours. A second pipe, used to drain the water from the pool, can empty the pool in 8 hours. The owner of the pool mistakenly opened both pipes. How long will it take to fill the pool if one pipe is filling and the other pipe is emptying?
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
1/a+1/b=1/x
1/4-1/8=1/x
8/32-4/32=1/x
4/32=1/x
x=32/4
x=8 hours working together
check
x/a+x/b=1
x/4+x/-8=1
8/4-8/8=1
2-1=1
1=1
ok
codewt

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