SOLUTION: 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?
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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? Answer by lwsshak3(11628) (Show Source):
You can put this solution on YOUR website! 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?
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let x=how long will it take for them to do the job working together
1/4=donald's work rate
1/6=mark's work rate
1/x=work rate working together
sum of indv. work rates=work rate working together
...
5/12=1/x
x=12/5
how long will it take for them to do the job working together=12/5 hrs
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