Solution (source code)

= Solution

The implication means that $A\subseteq B$, so $A\cap B=A$. By the definition of <conditional probability>,
$$
\boxed{P(A\mid B)=\frac{P(A\cap B)}{P(B)}
=\frac{1/3}{1/2}=\frac23}.
$$
This implication gives $P(B\mid A)=1$; it does not make the two <events> independent.