送交者: 草绿 于 July 27, 2009 01:50:41:
回答: 13 由 逻辑 于 July 27, 2009 00:43:40:
再跟俺哥对立一把：）
The question is: What is the greatest number of people with the same color hair
that we can be SURE to find in one of the these rooms?
As a probability problem, the probability of being blond and red should be given (Okay, we can assume equal probability as you did)
The number of ways putting 100 people in four rooms is C(103,100)=103x102x101/6. Hope I am correct on this. Anyway, the point here is there are many different ways for people to be partitioned in four rooms. Equal partition (your answer) is the MOST PROBABLE but NOT SURELY would occur as the problem asks. I can also say the answer is 0 because there is a probability of 1/C(103,100) that all the people are in one room and the other three rooms are empty (although this is much less SURE to happen:)) If your answer is correct, I can argue all the numbers from 0 to 100 are correct, albeit with less probability.
My point here is that there is no number that is SURE to happen as the problem asks. One thing for SURE is lala would refuse to say a word on the problem.:))
Am I missing something?