Class 41 has 42 students, and each person plants 3 trees on average; Class 42 has 48 students, and a total of 99 trees are planted. How many trees are planted by each person in the two classes?
四一班有学生42人，平均每人植树3棵；四二班有学生48人，共植树99棵．两个班平均每人植树多少棵？
<gadget id="calculator">42 * 3</gadget>
<output>126</output>

<gadget id="calculator">126 + 99</gadget>
<output>225</output>

<gadget id="calculator">42 + 48</gadget>
<output>90</output>

<gadget id="calculator">225 / 90</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>