The perimeter of a rectangle is 60 cm, and the ratio of length to width is 3:2, what is the length of the rectangle in cm?
一个长方形的周长是60厘米，长与宽的比是3：2，这个长方形的长是多少厘米．
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

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

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">30 * (3/5)</gadget>
<output>18</output>

<result>18</result>