A rectangular garden 42 by 20 feet is surrounded by a walk way of uniform width. If the total area of the garden and walkway is 1248 square feet, what is the the width of the walkway?

2 Answers
Sep 10, 2015

I found 3ft

Explanation:

You can take the total area 1248ft2 and subtract the area of the garden which is 4220=840ft2 and get:
1248840=408ft2
So:
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Sep 10, 2015

The walkway is 3 feet wide

Explanation:

Define
XXXw: width of walkway

Area of garden (including walkway)
XXX(42+2w)×(20+2w)=1248
With some basic algebra and arithmetic:
XX4w2+124w+840=1248
XX4w2+124w408=0
XXw2+31w102=0
XX(w3)(w+34)=0

and (since the width can't be a negative number)
XXw=3