Question 999725
It takes 28 minutes for 3 people to paint 7 walls.

How many minutes does it take 4 people to paint 10 walls?
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28*3 = 84 people-minutes for 7 walls.
--> 12 people-minutes for 1 wall.
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10*12 = 120 people-minutes for 10 walls.
120 people-minutes/4 people = 30 minutes