There are 40 boys in a class, the ratio of boys to girls is 4:3, how many girls are there?
某班男生有40人，男、女生人数的比是4：3，女生有多少人．
<gadget id="calculator">40 / 4</gadget>
<output>10</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<result>30</result>