There are 28 boys in Class 6 and 2. The ratio of boys to girls is 4:3. How many girls are there?
六2班男生人数是28人，男生和女生人数的比是4：3，女生有多少人．
<gadget id="calculator">28 / 4</gadget>
<output>7</output>

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<result>21</result>