4. There is a rectangular sheet, white on one side and gray on the other. It was folded as shown in the picture. The perimeter of the first rectangle is 20 more than the perimeter of the second rectangle. And the perimeter of the second rectangle is 16 more than the perimeter of the third rectangle. Find the perimeter of the original sheet.

![](https://cdn.mathpix.com/cropped/2024_05_06_9c213b8924a7544b7dc1g-2.jpg?height=231&width=351&top_left_y=130&top_left_x=1555)
Solution. From the figure, it can be seen that when folding, the perimeter of the rectangle decreases by twice the short side, so the short side of rectangle-1 is $20 / 2=10$, the short side of rectangle-2 is $16 / 2=8$. Therefore, the long side of rectangle-1 is 18, and the long side of the original sheet is 28. Thus, the perimeter is: $(28+18) \cdot 2=92$.

Criteria. An answer without justification or found by trial and error - 0 points.