if I have a garage and it takes 30 feet of Christmas lights

if I have a garage and it takes 30 feet of Christmas lights to outline my garage except along the ground how long is my garage door, x? if x- 3 is on both sides of the roof

Solution

The bottom is not included

Height of the top + 2 * height of roof = 30

x + 2 * (x-3) = 30

x + 2x - 6 = 30

3x = 36

x = 12 feets

Hence the length of the garage door is equal to 12 feet