The class held a welcome party. There were 30 students in total, and each person could get 7 oranges on average. Later, a few new guests came, and they were redistributed according to the current number of people. On average, each person could only get 5 oranges. Then how many new guests came.
班级开迎新晚会，共有30位同学，平均每人可以分得7个桔子．后来新来了几位客人，按现在的人数重新分配，平均每人只能分得5个桔子．后来新来了多少位客人．
<gadget id="calculator">30 / 5</gadget>
<output>6</output>

<gadget id="calculator">7 * 6</gadget>
<output>42</output>

<gadget id="calculator">42 - 30</gadget>
<output>12</output>

<result>12</result>