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Question 894215: It takes 3 people 2 1/2 hours to paint a large room. How long would it take 5 people to paint a similar room?
I tried 2 1/2 divided by 3, then multiplied that answer by 5. But I got 41/6 hours which did not make sense because it should be less time not more.
Answer by reviewermath(1029)   (Show Source):
You can put this solution on YOUR website! Q:
It takes 3 people 2 1/2 hours to paint a large room. How long would it take 5 people to paint a similar room?
I tried 2 1/2 divided by 3, then multiplied that answer by 5. But I got 41/6 hours which did not make sense because it should be less time not more.
A:
Use Inverse variation instead of Direct variation.
Let x = number of people
y = number of hours
If y varies inversely as x, then y = k/x where k is constant.
k = xy
k = 3(2 1/2) = 7 1/2
Therefore, if x = 5, then y = (7 1/2)/5 = 1 1/2
The answer is 1 1/2 hours or 1.5 hours.
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