document.write( "Question 558604: One pump fills a tank two times as fast as another pump. If the pumps work together they fill the tank in 18 minutes. How long does it take each pump working alone to fill the tank?
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Algebra.Com's Answer #363105 by Edwin McCravy(20055) $\"\"$ $\"About$

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One pump fills a tank two times as fast as another pump. If the pumps work together they fill the tank in 18 minutes. How long does it take each pump working alone to fill the tank?
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document.write( "Make this chart:\r\n" );
document.write( "================================================================\r\n" );
document.write( "                       number of       number of     rate in\r\n" );
document.write( "                      tanks filled      minutes    tanks/minute\r\n" );
document.write( "Slow pump alone          \r\n" );
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document.write( "Fast pump alone            \r\n" );
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document.write( "Both pumps together\r\n" );
document.write( "================================================================\r\n" );
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document.write( "Let the time for the fast pump to fill one tank be x minutes.\r\n" );
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document.write( "Fill in 1 for the number of tanks and x for the number of minutes\r\n" );
document.write( "for the fast pump alone:\r\n" );
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document.write( "================================================================\r\n" );
document.write( "                       number of       number of     rate in\r\n" );
document.write( "                      tanks filled      minutes    tanks/minute\r\n" );
document.write( "Slow pump alone            \r\n" );
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document.write( "Fast pump alone            1                x\r\n" );
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document.write( "Both pumps together\r\n" );
document.write( "================================================================\r\n" );
document.write( "

\n" ); document.write( ">>...One pump fills a tank two times as fast as another pump...<<
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document.write( "Since the slow pump takes twice as long as the fast pump, its time\r\n" );
document.write( "to fill one tank is 2x minutes.\r\n" );
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document.write( "Fill in 1 for the number of tanks and 2x for the number of minutes\r\n" );
document.write( "for the slow pump alone:\r\n" );
document.write( "\r\n" );
document.write( "================================================================\r\n" );
document.write( "                       number of       number of     rate in\r\n" );
document.write( "                      tanks filled      minutes    tanks/minute\r\n" );
document.write( "Slow pump alone            1               2x\r\n" );
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document.write( "Fast pump alone            1                x\r\n" );
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document.write( "Both pumps together\r\n" );
document.write( "================================================================\r\n" );
document.write( "

\n" ); document.write( ">>...If the pumps work together they fill the tank in 18 minutes...<<
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document.write( "Fill in 1 for the number of tanks and 18 for the number of minutes\r\n" );
document.write( "for both pumps pumping together:\r\n" );
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document.write( "\r\n" );
document.write( "================================================================\r\n" );
document.write( "                       number of       number of     rate in\r\n" );
document.write( "                      tanks filled      minutes    tanks/minute\r\n" );
document.write( "Slow pump alone            1               2x\r\n" );
document.write( "\r\n" );
document.write( "Fast pump alone            1                x\r\n" );
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document.write( "Both pumps together        1               18\r\n" );
document.write( "================================================================\r\n" );
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document.write( "Now we fill in the rates in tank/minute by dividing the number of\r\n" );
document.write( "tanks filled by the number of minutes:\r\n" );
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document.write( "================================================================\r\n" );
document.write( "                       number of       number of     rate in\r\n" );
document.write( "                      tanks filled      minutes    tanks/minute\r\n" );
document.write( "Slow pump alone            1               2x         \r\n" );
document.write( "Fast pump alone            1                x           \r\n" );
document.write( "Both pumps together        1               18          \r\n" );
document.write( "================================================================\r\n" );
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document.write( "The equation comes from\r\n" );
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document.write( "                       +  = \r\n" );
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document.write( "                             +  = \r\n" );
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document.write( "          Multiply through by LCD of 18x and solve\r\n" );
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document.write( "            Solution x = 27 minutes for the fast pump to fill 1 tank.\r\n" );
document.write( "                    2x = 2(27) = 54 minutes for the slow pump to fill 1 tank. \r\n" );
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document.write( "Edwin

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