Question

在 Annville Junior High School，数学俱乐部中 $30\%$ 的学生也在科学俱乐部，科学俱乐部中 $80\%$ 的学生也在数学俱乐部。科学俱乐部有 $15$ 名学生。数学俱乐部有多少名学生？

At Annville Junior High School, $30\%$ of the students in the Math Club are in the Science Club, and $80\%$ of the students in the Science Club are in the Math Club. There are $15$ students in the Science Club. How many students are in the Math Club?

$12$

$15$

$30$

$36$

$40$

答案：E

知识点：百分数

难度评级：1180

解答：

科学俱乐部的 $15$ 名学生中有 $80\%$ 也参加数学俱乐部，所以两个俱乐部共有的学生数是 $0.8\cdot 15=12$ 。这相当于数学俱乐部人数的 $30\%$ ，因此数学俱乐部有 $\dfrac{12}{0.3}=40$ 名学生。

所以正确答案是 E。

Since $80\%$ of the $15$ Science Club students are also in the Math Club, the two clubs overlap in $0.8\cdot 15=12$ students. This is $30\%$ of the Math Club, so the Math Club has $\dfrac{12}{0.3}=40$ students.

Thus, the correct answer is E .

1998 AMC 8 第 14 题

答案：E

难度评级：1180

解答：

其他年份的第 14 题