The school organizes 540 students in the fourth grade to plant trees. They should be divided into 9 tree planting sites, and each tree planting site is divided into 4 groups. How many people are there on average in each group?
学校组织四年级的540名学生去植树，要分成9个植树点，每个植树点分成4组，平均每组有多少人？
<gadget id="calculator">540 / 9 / 4</gadget>
<output>15</output>

<result>15</result>