There are 120 people in the 4 classes of the third grade participating in the interest group. If each class has 2 interest groups, how many people are there on average in each interest group?
三年级4个班有120人参加了兴趣小组，如果每个班有2个兴趣小组，平均每个兴趣小组有多少人？
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">120 / 8</gadget>
<output>15</output>

<result>15</result>