第3个回答 2020-07-01
P(A)=a
P(A|B)=b
P(B-A)=c
solution:
P(B-A)=c
P(B)-P(A∩B) =c
P(B) = c +P(A∩B)
//
P(A|B)=b
P(A∩B)/P(B)=b
P(A∩B)/[c +P(A∩B)]=b
P(A∩B)=bc +bP(A∩B)
P(A∩B) = bc/(1-b)
//
P(A+B)
= P(A) +P(B)-P(A∩B)
=a + c +P(A∩B) -P(A∩B)
=a+ c
//
P(A|~B)
=P(A∩~B)/P(~B)
=[P(A) -P(A∩B)]/[ 1-P(B)]
=[ a- bc/(1-b) ] /[ 1- c -P(A∩B)]
=[ a- bc/(1-b) ] /[ 1- c -bc/(1-b)]
= (a-ab -bc)/( 1-b- c)本回答被提问者采纳