If A and B are two events such that P(A) = 0.7, P(B) = 0.4 and P(A∩B¯)=0.5, where B¯ denotes the complement of B, then P(B/(A∪B-)) is equal to [2025]
(4)
P(A∩B¯)=P(A)–P(A∩B)
⇒ P(A∩B)=P(A)–P(A∩B¯)
=0.7 – 0.5 = 0.2
Now, P(A∪B¯)=P(A)–P(B¯)–P(A∩B¯)
= 0.7+(1– 0.4) – 0.5 = 0.8
P(B∩(A∪B¯))=P(B∩A)∪(B∩B¯)
=P(B∩A) [P(B∩B¯)=0]
= 0.2
Now, P(B/(A∪B¯))=P(B∩(A∪B¯))P(A∪B¯)=0.20.8=14.