[轉錄]◇ IMO 競賽第二題

[Zyca (swun mitru valy)]

    In a competition,there are a contestants and b judges,where b≧3 is
    an odd interger. Each judge rates each contestant either "pass" or "fail".
    Suppose k is a number such that,for any two judges,their ratings coincide
    for at most k contestants.Prove that

                 k     b-1
                ---≧ -----
                 a      2b

--
※ 發信站: 批踢踢實業坊(ptt.twbbs.org)
◆ From: ntucsn.csie.ntu.edu.tw