Board logo

标题: one of FF [打印本页]

作者: cook    时间: 2002-10-10 12:59     标题: one of FF

6、袋中有a只白球,b只红球,依次将球一只只摸出,不放回,求第K次摸出白球的概率
作者: tongxun    时间: 2002-10-10 16:58

cooK: I am not quiet sure.
[b/(a+b)]*[(b-1)/(a+b-1)]* ......*{ [ b-(k-2)]/[a+b-(k-2)] *(a/(a+b-k)




欢迎光临 国际顶尖MBA申请交流平台--TOPWAY MBA (http://forum.topway.org/) Powered by Discuz! 7.2