document.write( "Question 876489: An old computer takes 6 hours longer to process the company payroll than does a new computer. If it takes the two computers 4 hours to process the payroll working together, how long does it take each take computer working alone? \n" ); document.write( "

Algebra.Com's Answer #528796 by mananth(16946) $\"\"$ $\"About$

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completing pay roll = 1 job
\n" ); document.write( "let new computer take x hours to complete the job
\n" ); document.write( "New computer does 1/x of the job in 1 hour
\n" ); document.write( "Old computer does 1/(x+6) of the job in 1 hour\r
\n" ); document.write( "\n" ); document.write( "Together they do 1/4 of the job in 1 hour\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "1/x+ 1/(x+6) =1/4\r
\n" ); document.write( "\n" ); document.write( "solve\r
\n" ); document.write( "\n" ); document.write( " $\"%28%28x%2B6%29%2Bx%29+%2F%28x%28x%2B6%29%29=1%2F4\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"4%282x%2B6%29+=+x%5E2%2B6x\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"8x%2B24=x%5E2%2B6x\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2%2B6x-8x-24=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2-2x-24=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2-6x%2B4x-24=0\"$ \r
\n" ); document.write( "\n" ); document.write( "x(x-6)+4(x-6)=0\r
\n" ); document.write( "\n" ); document.write( "(x-6)(x+4)=0
\n" ); document.write( "x=6 OR x-4\r
\n" ); document.write( "\n" ); document.write( "ignore negative\r
\n" ); document.write( "\n" ); document.write( "new computer takes 6 hours
\n" ); document.write( "Old takes 6+6 =12 hours\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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