P(A)=1/4,P(B)=1/2,P(B|A)=1/3,则P(A+B)=?P(A拔B)=?

Question

P(A)=1/4,P(B)=1/2,P(B|A)=1/3,则P(A+B)=?P(A拔B)=?

Answer 1

P(AB)=P(A)*P(B|A)=1/4*1/3=1/12
P(A+B)=P(A)+P(B)-P(AB)=1/4+1/2-1/12=2/3
P(A拔B)=P(B)-P(AB)=1/2-1/12=5/12