Answer:
20x20 =400 then 400/25 = 16 Days
Explanation:
Always multiply the amounts of initial men x initail days
then divide by the new amount of men
With other questions for tag fish and sample fish in pond questions
They ask how many fish are estimated to be on the pond.
= The amount of fish caught next day divided by the amount of fish tagged and found in that same catch.
Then multiplied by the amount of all fish tagged initially the day before.
To find random amount in pool.
This is the same method but reversed.