
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 April 1, she catches a random sample of 80 fish, tags them, and releases them. On August 1, she catches a random sample of 100 fish and finds that 4 of them are tagged. To calculate the number of fish in the pond on April 1, she assumes that 30% of these fish are no longer in the pond on August 1 (because of death and emigrations), that 50% of the fish were not in the pond on April 1 (because of births and immigrations), and that the number of untagged fish and tagged fish in the August 1 sample are representative of the total population. What does the biologist calculate for the number of fish in the pond on April 1?

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