\[\boxed{\mathbf{285.}}\]
\[\textbf{а)}\ \left\{ 2;4;6 \right\};\]
\[N = 6;\]
\[N(A) = 3.\]
\[P = \frac{3}{6} = 0,5.\]
\[\textbf{б)}\ \left\{ 3;6 \right\};\]
\[N = 6;\]
\[N(A) = 2.\]
\[P = \frac{2}{6} = \frac{1}{3}.\]
\[\textbf{в)}\ \left\{ 4;5;6 \right\};\]
\[N = 6;\]
\[N(A) = 3;\]
\[P = \frac{3}{6} = 0,5.\]
\[\textbf{г)}\ Невозможное\ событие,\ \]
\[так\ как\ число\ благоприятных\ \]
\[исходов\ равно\ 0.\]
\[P = 0.\]