Answer:
width = 6in
length = 12in
Explanation:
If we call the width x, the length has to be 2x and so...
x + 2x + x + 2x = 36 (this can be simplified to ↓)
6x = 36 (if you divide both sides by 6...)
x = 6
This means that the width of the rectangle is 6in and so the length is 12in.
Hope this helps!