Question

四名学生参加考试。其中三人的分数是 $70, 80$ 和 $90$ 。如果四人平均分为 $70$ ，那么剩下那人的分数是多少？

Four students take an exam. Three of their scores are $70, 80,$ and $90.$ If the average of their four scores is $70,$ then what is the remaining score?

$40$

$50$

$55$

$60$

$70$

答案：A

知识点：平均数

难度评级：450

视频讲解：

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文字解答：

由平均分可知四人总分为 $4 \cdot 70 = 280$ 。因此剩下的分数为 $280 - 70 - 80 - 90 = 40.$

所以正确答案是 A。

From the average, we can calculate the sum of the scores to be $4 \cdot 70 = 280.$ This means that the remaining score is $280 - 70 - 80 - 90 = 40.$

Thus, A is the correct answer.

2016 AMC 8 第 3 题

答案：A

难度评级：450

视频讲解：

文字解答：

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