If two squares with side lengths of 5 cm are used to form a rectangle, what is the perimeter of the rectangle in cm?
用两个边长是5厘米的正方形拼成一个长方形，这个长方形的周长是多少厘米．
<gadget id="calculator">5 + 5 + 5</gadget>
<output>15</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>