
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
There is a bus leaving every 5 minutes between points A and B, traveling at a constant speed in both directions, and all buses have the same speed. Two people, Jia and Yi, start traveling towards each other at a constant speed from points A and B at the same time. Five minutes after they start, the first bus departs from both points A and B simultaneously. When Jia and Yi meet, Jia is overtaken by the 9th bus from point A, and Yi is overtaken by the 6th bus from point B. When Yi reaches point A, she is overtaken by the 8th bus from point B, and at this time, Jia is still 21 kilometers away from point B. What is Yi's speed in kilometers per hour?

Present the answer in LaTex format: \boxed{Your answer}
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