A rectangular piece of paper is folded into thirds to form a square with a perimeter of 20 cm. So what is the perimeter of the original rectangle in cm?
一张长方形的纸三等分折起后变成了一个正方形，正方形的周长是20厘米．那么原来长方形的周长是多少厘米．
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">5 + 15</gadget>
<output>20</output>

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>