document.write( "Question 393524: Computer A can do a job in 4 hours. Computer B can do the same job in 2 hours. How long will it take them to complete the job working together? \n" ); document.write( "

Algebra.Com's Answer #279268 by Earlsdon(6294) $\"\"$ $\"About$

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1) Find the hourly rate of computer A.
\n" ); document.write( "2) Find the hourly rate of computer B.
\n" ); document.write( "3) Add these to get the hourly rate of both computers working together.
\n" ); document.write( "4) Invert this number to get the time to complete the job working together.
\n" ); document.write( "If A can do the job in 4 hours, then it can do $\"1%2F4\"$ of the job in 1 hour.
\n" ); document.write( "If B can do the job in 2 hours, then it can do $\"1%2F2\"$ of the job in 1 hour.
\n" ); document.write( "Together, they can do $\"1%2F4%2B1%2F2+=+3%2F4\"$ of the job in 1 hour.
\n" ); document.write( "So, together, they can do the whole job in $\"4%2F3+=+1\"$ $\"1%2F3\"$ hours, or 1 hour and 20 minutes. \n" ); document.write( "

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