The perimeter of a rectangle is twice the sum of its length and its width. the perimeter is 16 meters and its length is 2 meters more than twice its width.

what is its length?

Let us assume the width of the rectangle = x meters
Then
Length of the rectangle = 2x + 2
Perimeter of the rectangle = 16 meters
Then
Perimeter = 2 (Length + width)
16 = 2(2x + 2 + x)
16 = 2(3x + 2)
16 = 6x + 4
6x = 16 - 4
6x = 12
x = 2
Then
Length of the side of the rectangle = 2x + 2
                                                       = (2 * 2) + 2
                                                       = 6
I hope that the procedure is clear enough for you to understand and this is the answer that you were looking for.

J= r + 9 because since jessica rode 9 more miles than roger, you add 9 miles to rogers mileage.