Question

A rectangular athletic field is twice as long as it is wide. If the perimeter of the athletic field is 120 yards, what are the dimensions ? what is the width ?

Answer 1

L=2W
P=2(L+W)
P=120
120=2(L+W)
divide by 2
60=L+W
sub 2W for L
60=2W+W
60=3W
divide by 60 both sides
20=W

width=20 yd

Answer 2

Given: $l=2w$ and $P=120yd$ find $l$ and $w$.

$P=2l+2w$
$120=2l+l$
$3l=120$
$l=40$

$l=2w$
$w=\frac{l}{2}$
$w=\frac{40}{2}$
$w=20$