Arug is to sit in a room so that a border of even width is left on all four sides. if the room is 12' x 15' in the area of the rug is 108 ft.², how wide with the border be?

A rug is to fit in a room so that a border of even width is left on all four sides.
If the room is 16 feet by 25 feet and the area of the rug is 220 square feet, how wide will the border
:
Let x = the width of the border around the rug
then
(25-2x) by (16-2x) the dimensions of the rug
:
The area equation
(25-2x)*(16-2x) = 220 sq/ft
FOIL
400 - 50x - 32x + 4x^2 = 220
:
Arrange as a quadratic equation
4x^2 - 82x + 400 - 220 = 0
:
4x^2 - 82x + 180 = 0

Simplify, divide by 2
2x^2 - 41x + 90 = 0
Factor
(2x - 5)(x - 18) = 0
Two solutions
2x = 5
x = 2.5 ft
and
x = 18 ft, obviously this not the solution
;
Border will be 2.5 ft
:
:
Check this by finding the dimension of the rug, and then the area
(25 - 2(2.5))*(16 - 2(2.5)) =
(25 - 5) * (16 - 5) =
20 * 11 = 220