1）6对茶杯和茶盖，2对是红的，2对是白的，2对是花的。随机在杯子放茶盖，没有一
对茶杯和盖子配套的概率是多大？
俺的解法：(2*4+2+2)/(6*6)=1/3
２）３００人有Ａ，Ｂ，Ｃ三种东西，有Ａ的占３５％，有Ｂ的占４５％，有Ｃ的占４
０％。只有１０％的人同时有两种东西。问只有一种东西的人大概是多少。
俺的解法：
Ｐ（A and B)+P(A and C)+P(B and C)-P(A and B and C)=0.1+2P(A and B and C)
P(A or B or C)=P(A)+P(B)+P(C)-P(A and B)-P(A and C)-P(B and C)+P(A and B and
C)
=P(A)+P(B)+P(C)-0.1-2*p(A and B and C)
1=0.35+0.45+0.4-0.1-2*P(A and B and C)
P(A and B and C)=0.05
so P(only A or only B or only C)=1-(P(A and B)+P(A and C)+P(B and C))
-2*P(A and B and
