9.5 $n$ is the smallest integer with the following property: it is a multiple of 15, and each of its digits is 0 or 8. Find $\frac{n}{15}$.
(2nd American Invitational Mathematics Examination, 1984)
[Solution] Since $n$ is a multiple of 15, $n$ is both a multiple of 5 and a multiple of 3. Because $n$ is a multiple of 5, its last digit can only be 0 or 5. According to the problem, every digit of $n$ is either 0 or 8, so the last digit of $n$ is 0.
Since $n$ is a multiple of 3, the number of 8s in $n$ must be a multiple of 3. To make $n$ as small as possible, $n$ should contain 3 eights. Therefore,
$$
\begin{array}{c}
n=8880 . \\
\frac{n}{15}=\frac{8880}{15}=592 .
\end{array}
$$