The Frog Experiment:

Professor Hopper, an environmental biologist, conducted a population study to determine the number of frogs that live in a pond near a state park. Since she could not catch all of the frogs in the pond she caught as frog example graphicmany as she could on her first trip to the pond, put a white band around their left hind leg, and put them back in the pond. A week later she returned to the pond, on her second trip, and again caught as many frogs as she could within the same amount of time. Here are the Professor’s data.frog example graphic

First trip to the pond:

58 frogs caught, banded, and released.


frog example graphicSecond trip to the pond:

72 frogs caught, of those 72 frogs 12 were banded.

frog example graphic


The professor assumed that the banded frogs had mixed thoroughly with all of the frogs in the pond, and from her data she was able to estimate the number of frogs that live in the pond.

frog example graphic


What do you think she concluded as to the total number of frogs in the pond?



More educator information see: Thinking Puzzles: Concrete and Formal Operational Thought Solutions