A park in the shape of a rectangle has dimensions 60m by 100m. If the park contains a rectangular garden enclosed by a concrete terrace, how wide is the terrace if the are of the garden is one-half the area of the park?

Answer 1

park area: 60*100 = 6000
If the terrace has uniform width w, then
garden area is (60-2w)(100-2w)

(60-2w)(100-2w) = 3000

Now just solve for w.