document.write( "Question 288966: An inlet pipe can fill a swimming pool in nine hours and an outlet pipe can empty a pool in 12 hours. Through an error both pipes were left open. How long will it take to fill the pool? \n" ); document.write( "
Algebra.Com's Answer #209367 by stanbon(75887)\"\" \"About 
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An inlet pipe can fill a swimming pool in nine hours and an outlet pipe can empty a pool in 12 hours. Through an error both pipes were left open. How long will it take to fill the pool?
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\n" ); document.write( "Inlet DATA:
\n" ); document.write( "time = 9 hrs/job ; rate = 1/9 job/hr
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\n" ); document.write( "Outlet pipe DATA:
\n" ); document.write( "time = 12 hr/job ; rate = 1/12 job/hr
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\n" ); document.write( "Together DATA:
\n" ); document.write( "time = x hr./job ; rate = 1/x job/hr
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\n" ); document.write( "Equation:
\n" ); document.write( "rate - rate = together rate
\n" ); document.write( "1/9 - 1/12 = 1/x
\n" ); document.write( "---
\n" ); document.write( "Multiply thru by 36x to get:
\n" ); document.write( "12x - 9x = 36
\n" ); document.write( "3x = 36
\n" ); document.write( "x = 12 hrs (time to fill the pool together)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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