Answer:
length = width + 10
4*width + 20 ≤ 90
width ≤ 17.5 feet
Explanation:
The perimeter of a rectangle is given by:
Perimeter = 2*length + 2*width
The length needs to be 10 feet longer than the width, so we have:
length = width + 10
Using this length in the perimeter equation, we have:
Perimeter = 2*(width + 10) + 2*width = 4*width + 20
The perimeter needs to be up to 90 feet, so we have:
P ≤ 90
4*width + 20 ≤ 90
4*width ≤ 70
width ≤ 17.5 feet
the maximum width of the garden is 17.5 feet