
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 estimate the population of a fish species in a large pond. On April 1, she captures and tags 120 fish, then releases them back into the pond. On August 1, she captures another sample of 150 fish, of which 5 are found to be tagged. She estimates that 30% of the fish present on April 1 have left the pond and that 50% of the fish in the August sample were not in the pond in April. Using this information, how many fish were in the pond on April 1?

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