
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
A biologist wants to calculate the number of fish in a pond. On June 1, he catches a random sample of 50 fish, tags them, and releases them back into the pond. On October 1, he catches another random sample of 80 fish and finds that 4 of them are tagged. He assumes that 30% of the fish are no longer in the pond on October 1 (due to death or migration) and that 35% of the fish caught in October were not in the pond on June 1 (due to births or migration). Based on this, what is the biologist's estimate for the number of fish in the pond on June 1?

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