document.write( "Question 298531: There are 720 dishes that need to be rinsed. John can rinse them in 144 minutes by himself. It will take his friend Bob 72 minutes to rinse these dishes. How long will it take them if they rinse these 720 dishes together? \n" ); document.write( "

Algebra.Com's Answer #214717 by stanbon(75887) $\"\"$ $\"About$

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There are 720 dishes that need to be rinsed. John can rinse them in 144 minutes by himself. It will take his friend Bob 72 minutes to rinse these dishes. How long will it take them if they rinse these 720 dishes together?
\n" ); document.write( "--------
\n" ); document.write( "John rate = 1/144 job/min
\n" ); document.write( "Bob rate = 1/72 job/min
\n" ); document.write( "-----
\n" ); document.write( "Together rate = 1/x job/min
\n" ); document.write( "===============================
\n" ); document.write( "Equation:
\n" ); document.write( "rate + rate = together rate
\n" ); document.write( "1/144 + 1/72 = 1/x
\n" ); document.write( "----
\n" ); document.write( "Multiply thru by 144x to get:
\n" ); document.write( "x + 2x = 144
\n" ); document.write( "3x = 144
\n" ); document.write( "x = 48 minutes (time for them to do the job together.
\n" ); document.write( "========================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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