If P(A)=0.5P(A) = 0.5P(A)=0.5 and P(A∪B)=0.8P(A \cup B) = 0.8P(A∪B)=0.8, and P(B∣A)=0.4P(B|A) = 0.4P(B∣A)=0.4, what is P(B)P(B)P(B)?
0.3
0.5
0.6
0.7