Question 1055956
A driveway is covered with concrete with an excess of 200 sq. ft. 
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and?
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A walkway is to be placed around a flower garden 20 * 15 ft. Determine walkway width. 
20 * 15 = 300 sq. ft. 
300 / 200 = 1.5 ft.
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Not enough info.
Is this related to the 200 sq ft mentioned above?
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Leftover or excess concrete is a volume, given in cubic feet.
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I don't mean to harass you, but your entry makes no sense.
Is English not your native language?