8瓶有一瓶中奖的概率：
(C2 1)(C22 7)/(C24 8)=341088/735471=46.3768%
楼主下面和标题不是一个问题
8瓶中一瓶,回家正好抽中那瓶
46.3768%/8=5.7971%
8瓶中两瓶
(C2 2)(C22 6)/(C24 8)=74613/735471=10.145%
然後10.145%/4=2.53623%
合8.3333..%=1/12
(341088/8+74613/4)/735471=8.3333333%=(8+1/3)/100=25/300=1/12