In the "Dragon Boat Festival" rice dumpling activity, the whole class is divided into three groups; the first group has 15 people, and each person makes 5 rice dumplings on average. The second group of 20 people made a total of 140 zongzi. The third group consisted of 15 people, making a total of 85 zongzi. How many zongzi does the whole class make on average?
"端午节"包粽子活动中，全班同学分成三个小组；第一小组15人，平均每人包粽子5个．第二小组20人，共包粽子140个．第三小组15人，共包粽子85个．全班同学平均每人包粽子多少个？
<gadget id="calculator">15 * 5</gadget>
<output>75</output>

<gadget id="calculator">75 + 140 + 85</gadget>
<output>300</output>

<gadget id="calculator">15 + 20 + 15</gadget>
<output>50</output>

<gadget id="calculator">300 / 50</gadget>
<output>6</output>

<result>6</result>