10-2. The large rectangle in the figure consists of 20 identical smaller ones. The perimeter of figure $A$ is 56 cm, the perimeter of figure $B$ is 56 cm. What is the perimeter of figure $C$? Provide your answer in cm.

|  | $A$ |  |  |
| ---: | :--- | :--- | :--- |
|  |  |  |  |
|  |  |  |  |
| $B$ |  |  | $C$ |
|  |  |  |  |
Answer: 40.

Solution: Let the horizontal size of the rectangle be $x$, and the vertical size be $y$. From the condition, we get the system of equations

$$
\left\{\begin{array}{l}
6 x+2 y=56 \\
4 x+6 y=56
\end{array}\right.
$$

We need to find what $2 x+6 y$ equals. Solving the system, we find $x=8, y=4$, from which $2 x+6 y=40$.