Let the width = x.
The length is 15 ft more than the width, so the length is x + 15.
The perimeter is less than or equal to 150 ft.
Perimeter formula:
P = 2L + 2W
The perimeter must be less than or equal to 150 ft.
[tex] 2L + 2W \le 150 [/tex]
Now we solve for x, the width.
[tex] 2(x + 15) + 2x \le 150 [/tex]
[tex] 2x + 30 + 2x \le 150 [/tex]
[tex] 4x + 30 \le 150 [/tex]
[tex] 4x \le 120 [/tex]
[tex] x \le 30 [/tex]
x is at most 30 ft.
x is the width.
The length is x + 15, so the length is 30 + 15 = 45.
The length is at most 45 ft.