Question

The length of a rectangle is four times its width. If the perimeter of the rectangle is 20 feet, how many feet long is the rectangle's length?

Answer 1

Largeur = x
longueur = 4 x 

2 ( x + 4 x) = 20
2 x + 8 x = 20 
10 x =20
x = 2

largeur  = 2 et longueur = 8