8. (7 points) A bag contains 10 white balls, 5 black balls, and 4 blue balls. All balls are identical except for their color. If $n$ balls are taken out, what is the minimum value of $n$ to ensure that at least 2 balls of each color are obtained? $\qquad$ .
【Solution】Solution: According to the analysis, we have
$$
\begin{array}{l}
n=10+5+2 \\
=15+2 \\
=17 \text { (pieces) }
\end{array}
$$

Answer: The minimum value of $n$ is 17.
Therefore, the answer is: 17.