2007 AMC 10A 第 12 题

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所有题目均经美国数学协会(MAA)官方合法授权使用。

12.

两名导游带领六名游客。导游决定分开行动。每名游客必须选择其中一名导游,但每名导游至少要带一名游客。导游和游客的不同分组共有多少种?

Two tour guides are leading six tourists. The guides decide to split up. Each tourist must choose one of the guides, but with the stipulation that each guide must take at least one tourist. How many different groupings of guides and tourists are possible?

5656

5858

6060

6262

6464

答案:D
知识点:乘法原理补集计数
难度评级:1330
解答:

每名游客独立选择两名导游之一,共有 26=642^6 = 64 种安排。

其中恰好有两种安排会让某名导游没有游客,所以答案为 642=6264 - 2 = 62

所以正确答案是 D

Each tourist independently chooses one of the two guides, giving 26=642^6 = 64 arrangements.

Exactly two of these leave a guide with no tourists, so the answer is 642=62.64 - 2 = 62.

Thus, the correct answer is D.

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