SOLUTION: 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?

Question 365424: 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?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Martha can rake the leaves in her yard in 4 hours.
So she does 1/4 of the job in 1 hour
Her younger brother can do the job in 6 hours.
so he can do 1/6 of the job in 1 hour
Together they will do 1/6 +1/4 of the job in 1 hour
= (2+3)/12
=5/12
They do 5/12 of the job in 1 hour
so they will do the job yogether in 12/5 hours
=2.4 hours
..
m.ananth@hotmail.ca
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