In a bar graph, 21 people are represented by 3.5 cm long bars, and 42 people are represented by how many centimeters of straight bars.
在一幅条形统计图中，用3.5厘米长的直条表示21人，用多少厘米的直条表示42人．
<gadget id="calculator">21 / 3.5</gadget>
<output>6</output>

<gadget id="calculator">42 / 6</gadget>
<output>7</output>

<result>7</result>