document.write( "Question 347781: Jack usually mows his lawn in 5 hours, Marilyn can mow the same lawn in 4 hours. How much time would it take for them to mow the lawn together.\r
\n" ); document.write( "\n" ); document.write( "They could mow the lawn in _?_ hours if they worked together. \n" ); document.write( "

Algebra.Com's Answer #248652 by stanbon(75887) $\"\"$ $\"About$

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Jack usually mows his lawn in 5 hours, Marilyn can mow the same lawn in 4 hours. How much time would it take for them to mow the lawn together.
\n" ); document.write( "They could mow the lawn in _?_ hours if they worked together.
\n" ); document.write( "---
\n" ); document.write( "Jack rate: 1/5 job/hr
\n" ); document.write( "Marilyn rate: 1/4 job/hr
\n" ); document.write( "-----
\n" ); document.write( "Together rate: 1/x job/hr
\n" ); document.write( "-----
\n" ); document.write( "Equation:
\n" ); document.write( "rate + rate = together rate
\n" ); document.write( "1/5 + 1/4 = 1/x
\n" ); document.write( "---
\n" ); document.write( "Multiply thru 20x to get:
\n" ); document.write( "4x + 5x = 20
\n" ); document.write( "---
\n" ); document.write( "9x = 20
\n" ); document.write( "x = 20/9
\n" ); document.write( "x = 2 2/9 hrs (time to do the job together)
\n" ); document.write( "================================================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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