请推荐一个最低调的相机吧。。。# PhotoGear - 摄影器材
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You are given 10 empty boxes. You distribute 5 black balls to these empty
boxes so that no two black balls can go into the same box. Now you have 4
white balls and you distribute them in the same fashion but this time a
white ball can go into a box where you put a black ball. That is, in the end
, you might have at least 5 full boxes or at most 9 full boxes. What is the
probability of choosing an empty box?
boxes so that no two black balls can go into the same box. Now you have 4
white balls and you distribute them in the same fashion but this time a
white ball can go into a box where you put a black ball. That is, in the end
, you might have at least 5 full boxes or at most 9 full boxes. What is the
probability of choosing an empty box?