一道概率题，帮帮忙

cuihua

从6双不同的手套中任取4只，求其中1双配对的概率。

我的答案，c6,1c10,2/c12,4

right answer is c6 1c5 2c2 1c2 1/c12 4

cranberry

如果在6副手套中，选出4支i，恰好是两副的概率，是否应为：c6,1*c5,1还是c6,2?

yayajiaojeff

以下是引用cuihua在2004-9-4 18:36:00的发言：

从6双不同的手套中任取4只，求其中1双配对的概率。

我的答案，c6,1c10,2/c12,4

right answer is c6 1c5 2c2 1c2 1/c12 4

Answer I: c6 1c5 2c2 1c2 1/c12 4I:    C6 1 -- take one pair from 6 different pairs; C5 2 -- from the 5 different pairs left choose two pairs, then for EACH pair, choose only ONE, which are C2 1 and C2 1, respectively.

Answer II: C6 1* C10 1 * C4 1 *(1/2):   C6 1 -- take one pair from 6 different pairs; C10 1--choose one from the 10 left; C8 1--take a Single one from or the FOUR pairs; 1/2 -- it would cause repetitive combination between C10 1 and C8 1 so that divide the result by 2.

Answer III: C6 1 * (C10 2 - C5 1):  C6 1 -- take one pair from 6 different pairs; (C10 2 - C5 1)--choose two from the 10 left, then deduct the combination for the same pair.

流沙

我的答案是（c(6,1)*c(10,2) - c(6,2))/c(12,4)

c(6,1)c(5,1)与c（6，2）含义是不同的，前者是有顺序的。

cranberry

是哦,只是这样的问话，应该不应该考虑顺序呢？

cranberry

所谓的正确答案就是考虑了顺序，或者默认了其中是有顺序的