There are 41 students in class 31. Each of them likes to eat at least one kind of fruit. There are 28 people who like apples, 25 people who like bananas, and how many people like to eat both kinds of fruits.
三1班共有41名同学，每人至少喜欢吃一种水果，喜欢吃苹果的有28人，喜欢吃香蕉的有25人，两种水果都喜欢吃的有多少人．
<gadget id="calculator">28 + 25</gadget>
<output>53</output>

<gadget id="calculator">53 - 41</gadget>
<output>12</output>

<result>12</result>