Question

一台口香糖球机中有 $9$ 个红色、 $7$ 个白色和 $8$ 个蓝色口香糖球。为了保证得到四个同色口香糖球，一个人至少必须购买多少个口香糖球？

A gumball machine contains $9$ red, $7$ white, and $8$ blue gumballs. The least number of gumballs a person must buy to be sure of getting four gumballs of the same color is

$8$

$9$

$10$

$12$

$18$

答案：C

知识点：抽屉原理

难度评级：980

解答：

最坏情况下，一个人可以先抽到 $3$ 个红球、 $3$ 个白球和 $3$ 个蓝球，共 $9$ 个球，还没有四个同色。

第 $10$ 个球必须与其中某一种颜色相同，从而得到四个同色。因此需要十个球。

所以正确答案是 C。

In the worst case, a person could draw $3$ red, $3$ white, and $3$ blue, which is $9$ gumballs, without yet having four of any color.

The next (tenth) gumball must match one of these colors, giving four of that color. So $10$ gumballs are needed.

Thus, the correct answer is C .

1994 AMC 8 第 21 题

答案：C

难度评级：980

解答：

其他年份的第 21 题