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1,A couple wants to tour four cities in Europe(London,Hamburg,Paris,and Zurich)on their honeymoon.If an irinerary is the order in which these cities will be visited,how many itineraries are possible?
2,How many ways can a committee of twenty people elect a president,secretary,and a treasurer?
人气:303 ℃ 时间:2020-05-10 15:27:46
解答
1,4*3*2*1=24
2,20*19*18=自己算一下吧
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