The school will plant 120 trees in spring, 40 of which have already been planted, and the rest will be divided into 6 groups with 5 people in each group. How many trees does each person plant on average?
学校春季要植120棵树，已经种植了40棵，剩下的分给6个组完成，每个组有5人．每人平均种多少棵？
<gadget id="calculator">90 / 30</gadget>
<output>3</output>

<result>3</result>