
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
Two boats, A and B, depart from locations A and B, which are $150$ km apart, and travel towards each other at a constant speed along the river. Boat A travels downstream from point A for $90$ km and meets boat B, which is traveling upstream from point B. Both boats have a speed of $30$ km/h in still water. What is the speed of the river in km/h?

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