document.write( "Question 917443: Working alone, John can do a job in 3 days. Harry could do the same job in 5 days. Assuming a day has 8 hours, how many hours will it take them working together to do the job, assuming their productivity does not change working together. \n" ); document.write( "

Algebra.Com's Answer #556717 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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Working alone, John can do a job in 3 days. Harry could do the same job in 5 days. Assuming a day has 8 hours, how many hours will it take them working together to do the job, assuming their productivity does not change working together.
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\n" ); document.write( "Change the time factor to hrs
\n" ); document.write( "then
\n" ); document.write( "John: 3*8 = 24 hrs
\n" ); document.write( "Harry: 5*8 = 40 hrs
\n" ); document.write( ":
\n" ); document.write( "Let t = no. of hrs required when working together
\n" ); document.write( "Let the completed job = 1
\n" ); document.write( ":
\n" ); document.write( "Each will do a fraction of the job, the two fractions add up to 1
\n" ); document.write( " $\"t%2F24\"$ + $\"t%2F40\"$ = 1
\n" ); document.write( "multiply equation by the least common multiple of 24 and 40; 120
\n" ); document.write( "Canceling the denominators results in:
\n" ); document.write( "5t + 3t = 120
\n" ); document.write( "8t = 120
\n" ); document.write( "t = 120/8
\n" ); document.write( "t = 15 hrs working together \n" ); document.write( "

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