原帖由 yuki319 於 2007-5-3 04:44 PM 發表
我再打了..
Five cards named A.B.C.D.E are turned face down and shuffled.
The cards are drawn one by one and put aside?
a)What is the chance that the first one is A?
b)Assume the first one is A,what is the channe that the second one is B?
[因為first要係A,所以要計埋抽左的的機會率先,而抽完次後會put aside,所以就淨番4張,B就佔了一張,所以係1/4,而呢種有關係的檮會率,即要完成條件一才可完成條件二的,就要把機會率乘起來]