Question

设A,B,C是随机事件,A与C互不相容,P(AB)=1/2, P(C)=1/3,则P(AB|-C)=?

Answer 1

P(AB|-C)

=P(AB-C)/P(-C)

=(P(AB)-P(ABC))/P(-C) ---->A, C不相容,P(AC)=0 P(ABC) =0

=P(AB)/P(-C)

=P(AB)/(1-P(C))

=3/4