Ans: (a) $\dfrac{8}{13}$ (b) $\dfrac{5}{13}$
- The required probability
$\begin{array}{cl}
= & \dfrac{C^8_4(C^2_1C^2_1C^2_1C^2_1)}{C^{16}_4} \\
= & \dfrac{8}{13}
\end{array}$ - The required probability
$\begin{array}{cl}
= & 1 – \dfrac{8}{13} \\
= & \dfrac{5}{13}
\end{array}$
