If A and B are two events such that P(A)=0.7, P(B)=0.4 and P(A ∩ B̄)=0.5, where B̄ denotes the complement of B, then P(B ∣(A ∪ B̄)) is equal to

If $\displaystyle A$ and $\displaystyle B$ are two events such that $\displaystyle P(A)=0.7, P(B)=0.4$ and $\displaystyle P(A \cap \bar{B})=0.5$, where $\displaystyle \bar{B}$ denotes the complement of $\displaystyle B$, then $\displaystyle P(B \mid(A \cup \bar{B}))$ is equal to