Question

A biologist catches 46 fish in a pond, tags them, and then releases them back into the pond. On a later visit to the pond, the biologist catches 20 fish, of which 8 are tagged.


Which is the best estimate for the number of fish in the pond?



66



115



368



920

Answer 1

$\dfrac{8}{20} = \dfrac{46}{x}$

$8x = 920 \\ x = 115$

Answer is 115.

Hope this helps. - M