回複：回複：need help, please!

來源: 於 2010-02-12 12:48:16 [舊帖] [給我悄悄話] 本文已被閱讀：次

I know how did you get the answer: E=(11,12,14,16,23,25,34,45).But the S=(11,22,33,44,55,66,12,13,14,15,16,23,24,25,26,34,35,36,45,46 56). So,N(S)is not 36.There is odd method :
P(E)=7.5/18=5/12,as P(11)=P(22)...P(66)=.5P(12)=...=.5P(56).