document.write( "Question 172783: art can do a job in 30 minutes bob can do it in 40 min. and carl can do it in 60 min , how long will it take them all to do the job if they help eachother, write the equation \n" ); document.write( "

Algebra.Com's Answer #127625 by Mathtut(3670) $\"\"$ $\"About$

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art can do 1/30 job per minute
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\n" ); document.write( "bob.......1/40 job per minute
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\n" ); document.write( "carl.......1/60 job per minute\r
\n" ); document.write( "\n" ); document.write( "those are all rates.....lets call time=t
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\n" ); document.write( "t/30+t/40+t/60=1(job)
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\n" ); document.write( "4t+3t+2t=120...muliply each term by 120
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\n" ); document.write( "9t=120
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\n" ); document.write( " $\"highlight%28t=120%2F9=40%2F3%29\"$ or 13 and 1/3 minutes to do the entire job... \n" ); document.write( "

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