Answer:
W = field width = 48 ft
Explanation:
Review: the formula for Perimeter of a rectangle is P = 2W + 2L.
Here we're told that the Perimeter is 168 ft. Therefore:
168 ft = 2L + 2W. But we are also told that W = 36 ft. Then:
168 ft = 2L + 2(36 ft) = 2L + 72 ft.
Subtracting 72 ft from both sides, we get 2L = 96, which tells us that:
L = 48 ft.
The field is 48 ft long.