The perimeter of a rectangle is 20 cm and the ratio of length to width is 3:2. What is the width of this rectangle in centimeters
长方形的周长是20厘米，长和宽的比是3：2．这个长方形的宽是多少厘米
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">10 * (2/5)</gadget>
<output>4</output>

<result>4</result>