The number of students in class 1 is between 30 and 40. If the ratio of boys to girls is 4:5, how many people are there in the class?
六1班人数在30～40人之间，已知男生与女生人数比为4：5，则全班有多少人．
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

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

<result>36</result>