There are 72 students in the sixth grade. The ratio of boys to girls is 5:4. How many girls are there?
六年级有学生72人，男生与女生人数的比是5：4，女生有多少人．
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">72 / 9</gadget>
<output>8</output>

<gadget id="calculator">8 * 4</gadget>
<output>32</output>

<result>32</result>