There are 3 classes in the third grade, and each class has 2 art groups. If there are 15 people in each art group, how many people in the third grade participated in the art group?
三年级有3个班，每个班有2个文艺小组．如果每个文艺小组有15人，三年级一共有多少人参加了文艺小组？
<gadget id="calculator">2 * 3 * 15</gadget>
<output>90</output>

<result>90</result>