You catch and tag 100 fish from a lake and release them unharmed. The next day you return and catch 100 fish again, but only 20 of them are tagged. Estimate the total number of fish in the lake.

Answer 1

Assume that in a day the 100 fish are distributed evenly throughout the population.

Since 20% of the 100 fish caught were tagged, you assume that 20% of the whole lake population are now tagged. So, if 100 tagged fish are 20%, there are 500 fish in the lake.

Answer 2

45

Answer 3

In a wildlife preserve 45 elephants are caught, tagged, and released. Later 52 elephants are caught and 13 of them have tags. Approximately, how many elephants are there in the wildlife preserve?
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