kazamii
幼苗
共回答了19个问题采纳率:78.9% 举报
我同意1楼,但一楼答案过程没看懂,这个说起来太烦了,但写吧!
1.和尾为0,有19,28,37,46,64,73,82,91.
P(0)=32/40*4/39=16/195
2.和尾为1,有01,10,29,38,47,56,65,74,83,92.
P(1)=40/40*4/39=4/39
3.和尾为2,有02,20,39,48,57,75,84,93
P(2)=32/40*4/39=16/195
4.和尾为3,有03,12,21,30,49,58,67,76,85,94
P(3)=40/40*4/39=4/39
5.和尾为4,有04,13,31,40,59,68,86,95
P(4)=32/40*4/39=16/195
6.和尾为5,有05,14,23,32,41,50,69,78,87,96
P(5)=4/39
7.和尾为6,有06,15,24,42,51,60,79,97
P(6)=16/195
8.和尾为7,有07,16,25,34,43,52,61,70,89,98
P(7)=4/39
9.和尾为8,有08,17,26,35,53,62,71,80
P(8)=16/195
10.和尾为9,有09,18,27,36,45,54,63,72,81,90
P(9)=4/39
11.两数相同,有00,11,22,33,44,55,66,77,88,99.
P(同数)=40/40*3/39=1/13
只是参考
1年前
10