Let the width be x
Therefore Length will be 4x - 7
Formula for perimeter of rectangle is:
2L + 2w = P (where L is length, w is width and P is perimeter.)
2(4x -7) + 2 (x) = 136
8x -14 + 2x = 136
8x + 2x = 136 + 14
10x = 150
x = 150/10
x = 15
The width is 15
therefore the length will be : 4(15) -7 → 60 - 7 = 53
The length is 53