SOLUTION: A rectangular garden is 60ft. by 80ft. Part of the garden is torn up to construct a sidewalk of uniform width around the garden. If the new area of the garden is 1/6 of the old are

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Question 8540: A rectangular garden is 60ft. by 80ft. Part of the garden is torn up to construct a sidewalk of uniform width around the garden. If the new area of the garden is 1/6 of the old area, how wide is the sidewalk?
Answer by glabow(165) About Me  (Show Source):
You can put this solution on YOUR website!
Think of this as a rectangle inside another rectangle. The outside rectangle is 60 by 80. The inside rectangle is less by how much? If you said that each side is two time less than the width of the sidewalk, you would be right! So the inside rectangle is 60-2x by 80 - 2x. We know that if you take 1/6 of the area of the outside rectangle, it is the area of the inside rectangle.
The outside is %2880%29%2860%29. The inside is %2860-2x%29%2880-2x%29. And the outside/6 equals the inside.
So,
%28%2880%29%2860%29%29%2F6=%2860-2x%29%2880-2x%29
Do the math.