Solution
= Solution
The single-roll colour probabilities are $1/2$, $1/3$ and $1/6$. There are $3!$ possible orders of the three distinct colours, and the independent rolls give each order probability $(1/2)(1/3)(1/6)$. The events are disjoint, so the required probability is
$$
\boxed{3!\,\frac12\,\frac13\,\frac16=\frac16.}
$$