There are 40 boys in class 62. The ratio of boys to girls is 10:9. How many girls are there?
六二班有男生40人，男生和女生人数的比是10：9，女生有多少人．
<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<gadget id="calculator">4 * 9</gadget>
<output>36</output>

<result>36</result>