SOLUTION: A sludge pool is filled by two inlet pipes. One pipe can fill the pool in 15 days, and the other can fill it in 21 days. However, if no sewage is added, continuous waste removal wi

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: A sludge pool is filled by two inlet pipes. One pipe can fill the pool in 15 days, and the other can fill it in 21 days. However, if no sewage is added, continuous waste removal wi      Log On

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Question 863186: A sludge pool is filled by two inlet pipes. One pipe can fill the pool in 15 days, and the other can fill it in 21 days. However, if no sewage is added, continuous waste removal will empty the pool in 36 days. How long will it take the two inlet pipes to fill an empty sludge pool.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
The description seems ambiguous regarding the continuous waste removal, but that process is not important to the question. IF sludge is being added, continuous waste removal is unspecified, and might be assumed not happening.

Fill rate for the empty pool: 1%2F15%2B1%2F21
%287%2B5%29%2F%283%2A5%2A7%29
12%2F105, pools per day, or 8%263%2F4 days to fill the sludge pool.