考试机经

qiqi

identical cars in 5 parking spaces. 3 red,1 bule, 1 yellow, how many arrangment ways could be?

kitten369

we should know how many cars first

qiqi

sorry,应该是 5 identical cars in 5 parking spaces. 3 red,1 bule, 1 yellow, how many arrangment ways could be?

betty_lee

有答案吗？ 这道题全没思路。 用排列还是组合？？？
谢谢指教！1

qiqi

请解释一下.

tongxun

我认为应该P5，5/P3，3 =20

先将5辆车排列，由于3辆车是一样的，再将这3辆车的排列除掉。

qiqi

谢谢

linlin315

以下是引用tongxun在2003-3-19 22:58:14的发言：
我认为应该P5，5/P3，3 =20

先将5辆车排列，由于3辆车是一样的，再将这3辆车的排列除掉。

likerock

Yes, I agree.  My answer is P(2,5)=20.  My thought is that I don't care the three red.  I just need to put that 1 yeallow and 1 blue in those 5 slots and the rest belongs to red cars.  So it's P(2,5).

自尊宝

两个是一样的。