document.write( "Question 878358: If donald can perfrom a job working alone in 4 hours,and his brother mark can do the same job in 6 hours, how long will it take for them to do the job working together? \n" ); document.write( "

Algebra.Com's Answer #530039 by lwsshak3(11628) $\"\"$ $\"About$

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If donald can perfrom a job working alone in 4 hours,and his brother mark can do the same job in 6 hours, how long will it take for them to do the job working together?
\n" ); document.write( "***
\n" ); document.write( "let x=how long will it take for them to do the job working together
\n" ); document.write( "1/4=donald's work rate
\n" ); document.write( "1/6=mark's work rate
\n" ); document.write( "1/x=work rate working together
\n" ); document.write( "sum of indv. work rates=work rate working together
\n" ); document.write( "...
\n" ); document.write( " $\"1%2F4%2B1%2F6=1%2Fx\"$
\n" ); document.write( " $\"3%2F12%2B2%2F12=1%2Fx\"$
\n" ); document.write( "5/12=1/x
\n" ); document.write( "x=12/5
\n" ); document.write( "how long will it take for them to do the job working together=12/5 hrs
\n" ); document.write( " \n" ); document.write( "

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