Alyssa wants to build a fence around her garden to keep deer and rabbits out. the length of the fence must be at least 50 ft, but she only has 140 ft for entire perimeter

The perimeter of a rectangle is twice the sum of the length and width:
P = 2(L + W)
Since we are given L >= 50 ft and P = 140 ft:
140 >= 2(50 + W)
70 >= 50 + W
20 >= W
Therefore, the width is less than or equal to 20 ft.

(The maximum area is 50 x 20 = 1000 ft^2.)