Math
posted by Aaron .
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?

area of walk of width w plus pool
(10+2w)(18+2w) = 180+429 = 609
4w^2 + 56w + 180 = 609
(2w11)(2w+39) = 0
e = 11/2