There are 4 groups in a class with equal number of students in each group. During the summer vacation, each person collected 16 excellent compositions. The school has started, and Mr. Wang counted it. The class collected a total of 640 excellent compositions. How many people are in each group?
一个班级有4组，每组人数相等．在暑假里每人收集了16篇优秀作文．开学了，王老师统计了一下．全班一共收集了640篇优秀作文．每组有多少人？
<gadget id="calculator">640 / 16 / 4</gadget>
<output>10</output>

<result>10</result>