document.write( "Question 949827: Officials begin to release water from a full man-made lake at a rate that would empty the lake in 6 weeks, but a river that can fill the lake in 20 weeks is replenishing the lake at the same time. How long does it take to empty the lake? Express your answer as a fraction reduced to lowest terms, if needed. \n" ); document.write( "

Algebra.Com's Answer #579891 by josgarithmetic(39618) $\"\"$ $\"About$

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Uniform fill or work rates, using the lake as the unit of volume, for 1 LAKE.
\n" ); document.write( "Time is quantity of weeks. Notice the filling rate uses less time than the emptying rate. The rate for both together is the sum of the individual rates. Understand that the two rates are of opposite signs.\r
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\n" ); document.write( "\n" ); document.write( " $\"1%2F6-1%2F20\"$ , LAKES per WEEK.\r
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\n" ); document.write( "\n" ); document.write( "You are finally interested in the reciprocal of that. How many weeks. \n" ); document.write( "

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