Question

汉密尔顿老师的八年级班想参加一年一度的三人篮球队锦标赛。兰斯、萨莉、乔伊和弗雷德被选为队员。三名首发队员有多少种选择方式？

Ms. Hamilton’s eighth-grade class wants to participate in the annual three-person-team basketball tournament. Lance, Sally, Joy, and Fred are chosen for the team. In how many ways can the three starters be chosen?

$2$

$4$

$6$

$8$

$10$

答案：B

知识点：组合补集计数

难度评级：660

小提示：

选择三名首发等同于选择谁不首发

Choosing the three starters is the same as choosing who sits out.

大提示：

有 $4$ 名可能不首发的队员

There are $4$ possible players who could be the alternate.

解答：

若有 $3$ 名首发，则有一人不首发。选择不首发的人就确定了首发。

不首发的人有 $4$ 种选择。

所以正确答案是 B。

If there are $3$ starters, then one person must not be starting. Choosing the person who doesn’t start determines the starters.

There are $4$ choices for the person who doesn’t start.

Thus, B is the correct answer.

2004 AMC 8 第 4 题

答案：B

难度评级：660

小提示：

大提示：

解答：

其他年份的第 4 题