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请帮帮我，帮我得到这块金子（图）

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楼主

发表于 2013-4-27 16:34:01 | 显示全部楼层

Condition on you see a gold box already. What is the sample space now?

p=2/3 is not correct.

And from the picture of the question, it seems he happen to open a upper box though he randomly choose the box position.

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9 主题	2658 帖子	1万积分

沙发

发表于 2013-4-27 16:47:57 | 显示全部楼层

If what he described in the picture is actual arrangement of the gold in the box (sample space), then

Pr(gold | a gold ) =1/2

Pr(gold | an upper box gold) = 1

When you open a box and see a gold, you obviously know: 1) it is a gold in stack, 2) it is upper or lower box.

From what the question ask: Bottom Box Gold probability =1

本贴由[NuBHH]最后编辑于：2013-4-27 8:49:40

本贴由[NuBHH]最后编辑于：2013-4-27 8:53:28

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