HELP ! I just don't get this. The perimeter of a rectangle is 40 m. The length is 5m more than twice the width. Find the dimensions. What is the length? What is the width? I need to simplify my answer...

PLEASE HELP ME>

2L + 2 W = 40 --> L+W = 20

L = 5 + 2 W

(5+2W) + W = 20
5 + 3 W = 20
3 W = 15
etc