The width of a rectangle is 5 meters and the length is 3 times the width. What is the perimeter of the rectangle?
一个长方形的宽是5米，长是宽的3倍，这个长方形的周长是多少米？
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

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

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

<result>40</result>