Students from 4 classes in the third grade participated in the rope skipping competition. Each class was divided into 2 groups, with an average of 15 people in each group. How many people are there?
三年级4个班的同学参加跳绳比赛，每班分2组，平均每组有15人．一共有多少人？
<gadget id="calculator">4 * 2 * 15</gadget>
<output>120</output>

<result>120</result>