SOLUTION: sally can paint a room in 5 hours while it takes Steve 7 hours to paint the same room. How long would it take them to paint the room if they worked together?

Question 994642: sally can paint a room in 5 hours while it takes Steve 7 hours to paint the same room. How long would it take them to paint the room if they worked together?
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
sally can paint a room in 5 hours while it takes Steve 7 hours to paint the same room. How long would it take them to paint the room if they worked together?
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Sally does 1/5 of a room per hour.
Steve does 1/7 of a room per hour.
Together --> 1/5 + 1/7 = 12/35 rooms per hour.
The inverse is hours per room = 35/12
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Parallel work is similar to parallel flow and parallel resistors.
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PS 5*7/(5+7) = 35/12

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