SOLUTION: if 3 men can paint 4 rooms in 9 hours how many hours and minutes will it take for one man to paint one room assuming he can work at the same rate alone?

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Question 376735: if 3 men can paint 4 rooms in 9 hours how many hours and minutes will it take for one man to paint one room assuming he can work at the same rate alone?
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
Let D = number of hours for painting job, r = number of rooms to paint/painted, and m = number of men doing the painting.
Then D is directly proportional to r but inversely proportional with m. Hence
D+=+%28kr%29%2Fm, where k is a constant of proportionality. To find k,
9+=+%28k%2A4%29%2F3, or k = 27/4. Hence D+=+%2827r%29%2F%284m%29. If m = 1 and r = 1, then D = 27/4 = 6.75, or 6 hours and 45 minutes.