If P(A∪B)=0.9P(A \cup B) = 0.9P(A∪B)=0.9, P(A)=0.6P(A) = 0.6P(A)=0.6, and P(B)=0.5P(B) = 0.5P(B)=0.5, what is P(Ac∣Bc)P(A^c | B^c)P(Ac∣Bc)?
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