SOLUTION: If Jim can paint a house in 3 hr and Robert can paint the same house in 5 hr, how long does it take them to paint it together?

Question 356284: If Jim can paint a house in 3 hr and Robert can paint the same house in 5 hr, how long does it take them to paint it together?
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
If Jim can paint a house in 3 hr and Robert can paint the same house in 5 hr, how long does it take them to paint it together?
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Look at how much each does per hour.
Jim does 1/3 of the job per hour.
Robert does 1/5 per hour.
Add those for the total per hour.
Invert it to get hours per job.

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