9. (5 points) A and B start running in opposite directions on a circular track at the same time and place. It is known that A's speed is $180 \mathrm{~m}$ per minute, and B's speed is $240 \mathrm{~m}$ per minute. Within 30 minutes, they meet 24 times. What is the maximum length of the track in meters?
【Analysis】Every time they meet, the two people run the full length of the track. Since they are running in opposite directions, first find the sum of their speeds, then multiply by the running time of 30 minutes, which can be used to find the length of 24 laps, and then divide by 24 to find the length of the track.

【Solution】Solution: $(180+240) \times 30 \div 24$
$$
\begin{array}{l}
=420 \times 30 \div 24 \\
=12600 \div 24 \\
=525 \text { (meters) }
\end{array}
$$

Answer: The length of the track is at most 525 meters.