Question

在一个由 $64$ 个单位正方形组成的棋盘上，随机选择一个单位正方形。所选正方形不接触棋盘外边缘的概率是多少？

On a checkerboard composed of $64$ unit squares, what is the probability that a randomly chosen unit square does not touch the outer edge of the board?

$\dfrac{1}{16}$

$\dfrac{7}{16}$

$\dfrac{1}{2}$

$\dfrac{9}{16}$

$\dfrac{49}{64}$

答案：D

知识点：基本概率

难度评级：980

解答：

内部正方形有个。 $(8 - 2)^2 = 6^2 = 36$

因此选中其中一个的概率是 $\dfrac{36}{64} = \dfrac{9}{16}.$

所以正确答案是 D。

There are $(8 - 2)^2 = 6^2 = 36$ squares on the interior.

This means that the probability of choosing one of these squares is $\dfrac{36}{64} = \dfrac{9}{16}.$

Thus, D is the correct answer.

2009 AMC 8 第 10 题

答案：D

难度评级：980

解答：

其他年份的第 10 题