Josh built his little brother a rectangular sandbox.  The perimeter of the sandbox is 30 feet and the length is twice the width. What is the width of the sandbox?
There are four sides to a rectangle, the width is W and so the length is 2W, and we can put that in this equation: W + W + 2W + 2W = 30 feet.
If we add the sides together, we get 6W = 30 feet.
To find W, we divide both sides by 6, like this: 6W / 6 = 30 feet / 6, so W = 5 feet.
#### 5