A rectangle whose length is 3 times its width and whose circumference is 48 centimeters, what is its width in centimeters?
一个长方形，长是宽的3倍，周长是48厘米，宽是多少厘米．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">48 / 2 / 4</gadget>
<output>6</output>

<result>6</result>