Application of linear systems

Question

An official playing field (including end zones) for the indoor football league has a length 40 yd longer than its width. The perimeter of the rectangular field is 200 yd.

Answer 1

l = 40 + w

p = 2l + 2w

2l + 2w = 200

2(40 + w) + 2w = 200

80 + 2w + 2w = 200

4w = 120

w = 30

l = 40 + w = 40 + 30 = 70

Width = 30 yds, Length = 70 yds