Question

一本杂志刊登了三位名人的照片，以及这三位名人婴儿时期的三张照片。婴儿照片没有标明对应的名人。读者被要求将每位名人与正确的婴儿照片配对。若读者随机猜测，三组都配对正确的概率是多少？

A magazine printed photos of three celebrities along with three photos of the celebrities as babies. The baby pictures did not identify the celebrities. Readers were asked to match each celebrity with the correct baby picture. What is the probability that a reader guessing at random will match all three correctly?

$\dfrac{1}{9}$

$\dfrac{1}{6}$

$\dfrac{1}{4}$

$\dfrac{1}{3}$

$\dfrac{1}{2}$

答案：B

知识点：基本概率排列

难度评级：940

解答：

读者给三位名人配对共有 $3! = 6$ 种方式。其中只有一种是正确配对。因此随机猜对全部三组的概率是 $\frac{1}{6}.$

所以正确答案是 B。

Notice that there are $3! = 6$ total ways that a reader could match the celebrities. However, only one of these is the correct matching. Therefore, the probability that the reader guesses it correctly is $\frac{1}{6}.$

Thus, B is the correct answer.

2014 AMC 8 第 12 题

答案：B

难度评级：940

解答：

其他年份的第 12 题