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箱子里有5个黑球,4个白球,每次随机取出一个球,若取出黑球,则放回箱中,重新取球...
箱子里有5个黑球,4个白球,每次随机取出一个球,若取出黑球,则放回箱中,重新取球;若取出白球,则停止取球,那么在第4次取球之后停止的概率为( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224817901411492/SYS201311012248179014114009_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224817901411492/SYS201311012248179014114009_ST/1.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224817901411492/SYS201311012248179014114009_ST/2.png)
D.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101224817901411492/SYS201311012248179014114009_ST/3.png)
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