document.write( "Question 1163560: a new type of pump can drain a pool in 6 hours. an older pump can drain the pool in 12 hours. how long will it take both pumps working together to drain the pool? \n" ); document.write( "
Algebra.Com's Answer #787698 by Alan3354(69443)\"\" \"About 
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a new type of pump can drain a pool in 6 hours. an older pump can drain the pool in 12 hours. how long will it take both pumps working together to drain the pool?
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\n" ); document.write( "6*12/(6+12) = 4 hours
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\n" ); document.write( "For A hours and B hours ---> A*B/(A+B)
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