Marianne wants to build a walkway around her rectangular garden. the width of her garden is one-third the length. the perimeter of marianne’s garden is 40 feet. what is the length and width of her garden?

Write a system of equation based on the problem
⇒First equation depicts "the width of her garden is one-third the length"


⇒Second equation depicts "the perimeter is 40 feet"
perimeter = 40
2l + 2w = 40
2(l + w) = 40
l + w = 40/2
l + w = 20

Solve the system of equation, substitute  as w to the second equation to find the length
l + w = 20


Equalize the denominators



Simplify the numerators

4l = 20 × 3
4l = 60
  l = 60/4
  l = 15
The length is 15 feet

Substitute the value of l to the first equation to find the width


w = 5
The width is 5 feet