Question

Lincoln 中学八年级有 $93$ 名学生。每名学生上数学课、外语课，或两者都上。八年级有 $70$ 人上数学课，有 $54$ 人上外语课。有多少八年级学生只上数学课而不上外语课？

The eighth grade class at Lincoln Middle School has $93$ students. Each student takes a math class or a foreign language class or both. There are $70$ eighth graders taking a math class, and there are $54$ eighth graders taking a foreign language class. How many eighth graders take only a math class and not a foreign language class?

$16$

$23$

$31$

$39$

$70$

答案：D

知识点：容斥原理韦恩图

难度评级：1070

视频讲解：

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文字解答：

两课都上的人数为 $70 + 54 - 93 = 31.$

从上数学课的总人数中减去两课都上的人数，得到只上数学课的人数为 $70 - 31 = 39$ 。

正确答案是 D。

The number of kids that are taking both classes is $70 + 54 - 93 = 31.$ Subtracting this from the number of kids taking a math class will give us the number of kids taking only a math class.

The desired number is $70 - 31 = 39.$

Thus, the correct answer is D.

2019 AMC 8 第 11 题

答案：D

难度评级：1070

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文字解答：

其他年份的第 11 题