2019 AMC10B 真题

2019 AMC 10B

Problem 1

Alicia had two containers. The first was full of water and the second was empty. She poured all the water from the first container into the second container, at which point the second container was full of water. What is the ratio of the volume of the first container to the volume of the second container?

Alicia 有两个容器，第一个里面的水是 满的，第二个是空的；她将第一个容器中的所有水倒 入第二个容器中，此时第二个容器中的水是 满的，较小容器的容积与较大容器的容积之比 是多少？

Problem 2

Consider the statement, "If is not prime, then is prime." Which of the following values of is a counterexample to this statement?

考虑论断：'如果 不是质数，那么 n n -2 就是质数。'以下的哪个 值是此论断的反例？ n

Problem 3

In a high school with students, of the seniors play a musical instrument, while of the non-seniors do not play a musical instrument. In all, of the students do not play a musical instrument. How many non-seniors play a musical instrument?

在一所有 500 名学生的高中， 40% 的高三学生会演奏乐器，而 30% 的非高三学生不会演奏乐 器。整体而言， 46.8% 的学生不会演奏乐器。有多少非高三学生会演奏乐器？

(A) 66 (B) 154 (C) 186 (D) 220 (E) 266