A tree planting group consists of 10 people. Among them, 4 people each planted 20 trees, 4 people each planted 15 trees, and 2 people each planted 10 trees. The average number of trees planted by each person in this group.
一个植树小组共10人．其中，有4人各植树20棵，有4个各植树15桂林，有2人各植树10棵．这个小组平均每人植树多少棵．
<gadget id="calculator">4 * 20</gadget>
<output>80</output>

<gadget id="calculator">4 * 15</gadget>
<output>60</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">80 + 60 + 20</gadget>
<output>160</output>

<gadget id="calculator">160 / 10</gadget>
<output>16</output>

<result>16</result>