A rectangular garden was planted measures 12 ft by 8 ft. You want to plant a border of roses around the garden of equal width with the same area as the garden. What should the width of the border of roses be?

Answer 1

the area of the garden is 96 ft^2
So, you want the walk of width w to also have 96 ft^2 of area. That means that

(12+2w)(8+2w) = 96+96

Now just solve for w.