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If the length of a rectangular parking lot is ten meters less than twice its width and the perimeter is 400 meters, find the length of the parking lot
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Let W be the width of the parking lot.
Then its length is (2W-10) meters, according to the solution.
Next, you have this equation for the perimeter:
w + (2W-10) + W + (2W-10) = 400 or
6W - 20 = 400,
6W = 400 + 20 = 420,
W = = 70 meters is the width.
Then the length is 2*70-10 = 130 meters.
Solved. The dimensions are 130 m and 70 m.