By the conditional probability formula,
P(A|B)=P(A∩B)P(B)0.1=P(A∩B)0.4P(A∩B)=0.04∎
P(A′∩B) is the probability that event B occurs and event A does not occur ∎
Using P(A)=0.6 and P(A∩B)=0.04,
P(A′∪B)=1−0.56=0.44∎