Question

The length of a rectangle is twice the width. If the length is increased by 6, and the width is doubled, a new rectangle is formed whose perimeter is 20 more than the perimeter of the original rectangle. Find the dimensions of the original rectangle.

Answer 1

old perimeter is 2(w+2w)
so,

2(2*w+ 2w+6) = 2(w+2w)+20

Now you can find w and 2w.

Answer 2

Length is 8
Width is 4