Solution
= Solution
Insert the values from (a) into <Bayes' theorem>:
$$
\frac{P(A\mid B)P(B)}{P(A)}
=\frac{(4/5)(5/9)}{13/18}=\frac8{13}=P(B\mid A).
$$
Thus the identity is \b[satisfied]. Equivalently, both $P(A\mid B)P(B)$ and $P(B\mid A)P(A)$ equal the joint <probability> $4/9$.