SOLUTION: Dixie can paint a room in 3 hours working alone. Trixie can paint the same room in 6 hours working alone. How long after Dixie starts to paint the room will it be finished if Tri

Question 321294: Dixie can paint a room in 3 hours working alone. Trixie can paint the same room in 6 hours working alone. How long after Dixie starts to paint the room will it be finished if Trixie joins her 1 hour later?
Answer by mananth(16949) (Show Source): You can put this solution on YOUR website!
Dixie can paint a room in 3 hours working alone.
So she can do 1/3 of the job in 1 hour.
Trixie can paint the same room in 6 hours
So she can do 1/6 of the job in 1 hour.
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Trixie joins 1 hour late
..
Dixie has done 1/3 of the job
When Trixie joins only 1-1/3 of the job is remaining
= 2/3 of the job.
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Together they do 1/3 +1/6 of the job in 1 hour.
=2+1/ 6
=1/2 the job in 1 hour.
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1/2 job they together do in 1 hour
2/3 of job they will do in 2/3 / 1/2
=2/3 * 2
1 1/3 hours
They will finish the job in 1 1/3 hours.