A man built a walk of uniform width around a rectangular pool. If the area of the walk is 429 square feet and the dimensions of the pool are 10 feet by 18 feet, how wide is the walk?

Answer 1

area of walk of width w plus pool

(10+2w)(18+2w) = 180+429 = 609
4w^2 + 56w + 180 = 609
(2w-11)(2w+39) = 0
e = 11/2