AMC 8 1989 Problem 9

AMC8 1989 年第 9 题

比与比例★★☆☆☆

There are 2 boys for every 3 girls in Ms. Johnson's math class. If there are 30 students in her class, what percent of them are boys?

Ms. Johnson 的数学班上每 2 个男生对应 3 个女生。如果她班上有 30 名学生，男生占百分之多少？

正确答案 · Correct Answer

解析 · Solution

Solution 1

Since the ratio of boys to girls is

2:3

\displaystyle \frac{2}{2+3} = \frac{2}{5} = 40\%

of the students are boys. The number of students in the class is irrelevant.

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