document.write( "Question 916669: Together it takes Sally and Tom 42 minutes to complete a job. Alone, Sally completes the job 13 minutes faster than Tom. How long will it take tom to complete the job alone? 12 U Advanced Functions question! \n" ); document.write( "

Algebra.Com's Answer #556199 by lwsshak3(11628) $\"\"$ $\"About$

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Together it takes Sally and Tom 42 minutes to complete a job. Alone, Sally completes the job 13 minutes faster than Tom. How long will it take tom to complete the job alone?
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\n" ); document.write( "let x=time Tom can do the job alone
\n" ); document.write( "1/x=Tom's work rate
\n" ); document.write( "x-13=time Sally can do the job alone
\n" ); document.write( "1/(x-13)=Sally's work rate
\n" ); document.write( "42=time Sally and Tom working together can finish the job
\n" ); document.write( "1/42=their work rate
\n" ); document.write( "..
\n" ); document.write( "indv. work rates =work rate working together
\n" ); document.write( " $\"1%2Fx%2B1%2F%28x-13%29=1%2F42\"$
\n" ); document.write( "lcd:x(x-13)
\n" ); document.write( "x-13+x=x(x-13)/42
\n" ); document.write( "2x-13=(x^2-13x/42
\n" ); document.write( "84x-546=x^2-13x
\n" ); document.write( "x^2-97x+546=0
\n" ); document.write( "(x-6)(x-91)=0
\n" ); document.write( "x=91
\n" ); document.write( "time Tom can do the job alone=91 min \n" ); document.write( "

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