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 many as she could in one day, put a white band around their left hind leg, and put them back in the pond.  A week later she returned to the pond and again caught as many frogs as she could within the same amount of time.  Here are the Professor’s data.

  First trip to the pond

         58 frogs caught and banded

 

Second trip to the pond

         72 frogs caught, of those 72 frogs 12 were banded

 

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

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.

 

Teacher information see Thinking Puzzles: Concrete and Formal Operational Thought Solutions