If the width of a rectangle is 4 cm and the length is 3 times the width, what is the perimeter of the rectangle in cm?
一个长方形的宽是4厘米，长是宽的3倍，这个长方形的周长是多少厘米．
<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<gadget id="calculator">12 + 4</gadget>
<output>16</output>

<gadget id="calculator">16 * 2</gadget>
<output>32</output>

<result>32</result>