Some students are playing Three Kingdoms. At this time, Mr. Wu wanted to join with as many cards as his age. After Mr. Wu joined, the average age of all students rose from 11 to 12. The average number of cards brought by each person has been reduced from 47 to 45. So how many students are there in total?
一些同学正在玩三国杀．这时吴老师带着和他年龄一样多的卡片想要加入．吴老师加入后，所有学生的平均年龄从11岁涨到12岁．平均每人带的卡片数从47张降低到45张．那么，共有多少名同学．
<gadget id="calculator">45 - 12</gadget>
<output>33</output>

<gadget id="calculator">33 / 3</gadget>
<output>11</output>

<result>11</result>