AMC8 1990

AMC8 1990 · Q9

AMC8 1990 · Q9. It mainly tests Fractions, Averages (mean).

The fifteen scores in Mr. Freeman's class were: 89, 72, 54, 97, 77, 92, 85, 74, 75, 63, 84, 78, 71, 80, 90. In Mr. Freeman's class, what percent of the students received a grade of C?

弗里曼先生班上的 15 个成绩是：89, 72, 54, 97, 77, 92, 85, 74, 75, 63, 84, 78, 71, 80, 90。在弗里曼先生班上，有百分之多少的学生获得 C 等级？

(A) 20% 20%

(B) 25% 25%

(D) 33 1/3% 33 1/3%

(E) 40% 40%

Answer

Correct choice: (D)

正确答案：（D）

Solution

Five of the fifteen scores [77, 75, 84, 78, 80] are in the “C range”, so $5/15 = 1/3 = 33\frac{1}{3}\%$.

15 个成绩中有 5 个 [77, 75, 84, 78, 80] 在“C 范围”内，所以 $5/15 = 1/3 = 33\frac{1}{3}\%$。

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