Question

一位老师给一个班考试，其中 $10\%$ 的学生是低年级生， $90\%$ 是高年级生。考试平均分为 $84$ 。低年级生都得了同一个分数，高年级生平均分为 $83$ 。每个低年级生得了多少分？

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：平均数比与比例

难度评级：1330

解答：

假设班上有 $10$ 名学生：一名低年级生和九名高年级生。总分为 $10\cdot 84=840$ 。

九名高年级生总分为 $9\cdot 83=747$ ，所以低年级生的分数为 $s=840-747=93$ 。

所以正确答案是 C。

Suppose the class has $10$ students: one junior and nine seniors. The total of all scores is $10\cdot 84=840.$

The nine seniors total $9\cdot 83=747,$ so the junior's score is $s=840-747=93.$

Thus, the correct answer is C.

2007 AMC 10B 第 16 题

答案：C

难度评级：1330

解答：

其他年份的第 16 题