If the length of a rectangle is 20 cm and the length is 4 times the width, what is the perimeter of the rectangle in cm?
一个长方形的长20厘米，长是宽的4倍，这个长方形的周长是多少厘米．
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">20 + 5</gadget>
<output>25</output>

<gadget id="calculator">25 * 2</gadget>
<output>50</output>

<result>50</result>