What is the length of a rectangle 3 times the width the perimeter is 20?

Question

This is for my algebra class

Answer 1

Perimeter = 2L + 2W. The problem tells us that L = 3W and P = 20.

Substituting:2(3W) + 2W = 20

6W + 2W = 20

8W = 20 W = 20/8 = 2 4/8 = 2 1/2

so W = 2 1/2.

L = 3(2 1/2) = 7 1/2.

Check: 2(7 1/2) + 2(2 1/2) = 15 + 5 = 20