document.write( "Question 441446: John can wash and wax a car in 4 hours. Max can wash and wax a car in 5 hours. How long would it take them to do it together? \n" ); document.write( "

Algebra.Com's Answer #304707 by stanbon(75887) $\"\"$ $\"About$

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John can wash and wax a car in 4 hours. Max can wash and wax a car in 5 hours. How long would it take them to do it together?
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\n" ); document.write( "John's rate = 1/4 job/hr
\n" ); document.write( "Max's rate = 1/5 job/hr
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\n" ); document.write( "Together rate = 1/x job/hr
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\n" ); document.write( "Equation:
\n" ); document.write( "rate + rate = together rate
\n" ); document.write( "1/4 + 1/5 = 1/x
\n" ); document.write( "Multiply thru by 20x to get:
\n" ); document.write( "5x + 4x = 20
\n" ); document.write( "9x = 20
\n" ); document.write( "x = 20/9 = 2 2/9 hrs (time to do the job together)
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\n" ); document.write( "2 2/9 hrs = 2 hrs (2/9)60 minutes = 13 min 20 seconds
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\n" ); document.write( "Final Answer: 2 hrs 13 min 20 seconds
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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