Question

一位老师给一个班考试，班上 $10\%$ 是三年级学生， $90\%$ 是四年级学生。全班平均分为 $84$ 。所有三年级学生得分相同，四年级学生平均分为 $83$ 。每个三年级学生得了多少分？

A teacher gave a test to a class in which $10\%$ of the students are juniors and $90\%$ are seniors. The average score on the test was $84.$ The juniors all received the same score, and the average score of the seniors was $83.$ What score did each of the juniors receive on the test?

$85$

$88$

$93$

$94$

$98$

答案：C

知识点：平均数百分数

难度评级：1330

解答：

取班上有 $10$ 名学生，则有 $1$ 名三年级和 $9$ 名四年级。

全班总分为 $10\cdot84=840$ ，四年级学生贡献 $9\cdot83=747$ 。 $840-747=93.$

所以正确答案是 C。

Take a class of $10$ students, so there is $1$ junior and $9$ seniors.

The total of all scores is $10\cdot84=840,$ and the seniors contribute $9\cdot83=747.$ So the junior scored $840-747=93.$

Thus, the correct answer is C.

2007 AMC 12B 第 12 题

答案：C

难度评级：1330

解答：

其他年份的第 12 题