Bonnie and Bruce have a rectangular swimming pool that is 6 feet wide and 10 feet long. They are going to build a tile border of uniform width around the pool. They have a 105 square feet of tile.

Question

How wide should the border be?

Answer 1

you want the total area, less the pool, to be 105. So, that means that the border has width x, where

(6+2x)(10+2x)-(6)(10) = 105
x = 5/2 ft or 2'6"