\[\boxed{\mathbf{82.}}\]
\[\textbf{а)}\ Да,\ несовместные.\]
\[\textbf{б)}\ P(A) = \frac{1}{2};\ \ P(B) = \frac{1}{6}:\ \]
\[P(A \cup B) = P(A) + P(B) =\]
\[= \frac{1}{2} + \frac{1}{6} = \frac{3}{6} + \frac{1}{6} = \frac{4}{6} = \frac{2}{3}.\]