document.write( "Question 978129: Martha can rake the leaves in her yard in 4 hours. her younger brother can do the job in 6 hours. How long will it take them to do the job if they work together? \n" ); document.write( "

Algebra.Com's Answer #599620 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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Martha can rake the leaves in her yard in 4 hours.
\n" ); document.write( " her younger brother can do the job in 6 hours.
\n" ); document.write( " How long will it take them to do the job if they work together?
\n" ); document.write( ":
\n" ); document.write( "Let t = time required when they work together
\n" ); document.write( "let the completed job = 1
\n" ); document.write( ":
\n" ); document.write( "Each will do a fraction of the job, the sum of the fractions = 1
\n" ); document.write( " $\"t%2F4\"$ + $\"t%2F6\"$ = 1
\n" ); document.write( "multiply equation by the least common multiple of the denominators, 12.
\n" ); document.write( "12* $\"t%2F4\"$ + 12* $\"t%2F6\"$ = 12(1)
\n" ); document.write( "Cancel the denominators, and you have
\n" ); document.write( "3t + 2t = 12
\n" ); document.write( "5t = 12
\n" ); document.write( "t = 12/5
\n" ); document.write( "t = 2.4 hrs working together which is; 2 + .4(60) = 2 hrs 24 min \n" ); document.write( "

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