[問題] 排列組合..
將 1,1,1,1,2,2,2,3,3,3,3,3,3,3,4,4,4,4,4,4
四個1 三個2 七個3 六個4 依照數字分成四類
混合後由其中任取四個數字成一組,共可組成多少組?
Ans:34
以下是我的作法...
四同:C(3,1)=3
三同一異:C(4,1)C(3,1)=12
二同二異:C(4,1)C(3,2)=12
二同 另一組二同:C(4,1)C(3,1)=12
四異:4
共43組
請問哪裡寫錯了@@?
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09/11 13:17, , 58F
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