1、15人中取5人,有3个不能都取,有多少种取法?
C155 C122
2、7人比赛,A在B的前面的可能性有多少种
P77 / 2 A在B前的次数与在其后的次数相等
3、3对人分为A,B,C三组,考虑组顺和组中的人顺,有多少种分法?
P33 3 先考虑组顺,再考虑人顺
4、17个人中任取3人分别放在3个屋中,其中7个只能在某两个屋,另外10个只能在另一个屋,有多少种分法?
P72 P101
5、A,B,C,D,E,F排在1,2,3,4,5,6这六个位置,问A不在1,B不在2,C不在3的排列的种数?
P66 -3P55 +3P44 -P33
6、4幅大小不同的画,要求两幅最大的排在一起,有多少种排法?
2P33
7、5辆车排成一排,1辆黄色,1两蓝色,3辆红色,且3辆红车不可分辨,问有多少种排法?
P55 /P33 如果再加一个条件2辆不可分辨的白色车,同理:P77 /P33 P22
8、4对夫妇,从中任意选出3人组成一个小组,不能从任一对夫妇中同时选择两人,问符合选择条件的概率是多少?
/C83
9、从6双不同的手套中任取4只,求其中恰有一双配对的概率。
C61 C52 C21 C21 /C124
10、3个打字员为4家公司服务,每家公司各有一份文件录入,问每个打字员都收到文件的概率?
C31 /34 先把文件分为2,1,1三堆,然后把这三堆文件分给三个打字员。
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