2006 AMC 12B 第 7 题

Question

Lopez 先生和 Lopez 太太有两个孩子。他们上家庭汽车时，两个人坐在前排，另外两个人坐在后排。Lopez 先生或 Lopez 太太必须坐在驾驶座。共有多少种座位安排？

Mr. and Mrs. Lopez have two children. When they get into their family car, two people sit in the front, and the other two sit in the back. Either Mr. Lopez or Mrs. Lopez must sit in the driver’s seat. How many seating arrangements are possible?

4

12

16

24

48

答案：B

知识点：乘法原理有限制的排列

难度评级：1180

小提示：

按顺序安排座位：驾驶座、副驾驶座，然后是两个后排座位

Fill the seats in order: driver, then front passenger, then the two back seats

大提示：

驾驶座有

2

种选择，副驾驶座有

3

种选择，后排有

2

种顺序

There are

2

choices for the driver and

3

for the front passenger, then

2

orders in back

解答：

驾驶员是两位父母之一：有

2

种选择。

剩下的

3

人中任意一人可以坐副驾驶座，最后

2

人坐后排，有

2

种顺序。

总数为

2 \cdot 3 \cdot 2 = 12

。

因此，正确答案是 B。

The driver is one of the two parents:

2

choices.

Any of the remaining

3

people can sit in the front passenger seat, and the last

2

people fill the back in

2

orders.

The total is

2 \cdot 3 \cdot 2 = 12.

Thus, the correct answer is B.

2006 AMC 12B 第 7 题

答案：B

难度评级：1180

小提示：

大提示：

解答：

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