Answer:the warehouse's width is 100 feet.
Step-by-step explanation:
Let L represent the length of the rectangular warehouse.
Let W represent the width of the rectangular warehouse.
The rectangular warehouse was 20 feet longer than 3 times its width. This means that
L = 3W + 20
The perimeter of a rectangle is
the sum of all its sides. Therefore, the formula for determining the perimeter of a rectangle expressed as
Perimeter = (L + W)
If the perimeter of the warehouse was 840 feet, it means that
2(L + W) = 840
Dividing through by 2, it becomes
L + W = 420- - - - - - - - 1
Substituting L = 3W + 20 into equation 1, it becomes
3W + 20 + W = 420
4W = 420 - 20
4W = 400
W = 400/4 = 100
