9. (6 points) A hollow cone and a hollow cylinder, with base inner radii and heights of $12 \mathrm{~cm}, 20 \mathrm{~cm}$ respectively, are combined to form a vertically placed container as shown in the figure. Some fine sand is poured into this container, filling the cone and part of the cylinder. It is measured that the sand in the cylinder is $5 \mathrm{~cm}$ high. If the container is inverted, the height of the sand is $-11 \frac{2}{3} \_\mathrm{cm}$.
【Solution】Solution: According to the analysis, the height of the sand is: $5+20 \div 3=11 \frac{2}{3}$ (cm); Answer: The height of the sand is $11 \frac{2}{3}$ cm.
Therefore, the answer is: $11 \frac{2}{3}$.

Note: The negative sign in the problem statement is likely a typographical error and should be disregarded.
9. (6 points) A hollow cone and a hollow cylinder, with base inner radii and heights of $12 \mathrm{~cm}, 20 \mathrm{~cm}$ respectively, are combined to form a vertically placed container as shown in the figure. Some fine sand is poured into this container, filling the cone and part of the cylinder. It is measured that the sand in the cylinder is $5 \mathrm{~cm}$ high. If the container is inverted, the height of the sand will be $\qquad$ $\mathrm{cm}$.