ANSWER
6w = 100
EXPLANATION
The formula for calculating the perimeter of a rectangular building is P=2l +2w.
From the question, the perimeter of the garden is 100 feet.
It was given that, the length of a rectangular garden is 3 times the width.
This implies that,
[tex]l = 3w[/tex]
We substitute into the formula to get:
[tex]2(3w)+2w = 100[/tex]
[tex]6w+2w = 100[/tex]
This simplifies to:
[tex]8w = 100[/tex]
