Identifying Errors In Reasoning


Work Time


Karen read that the population of birds on an island increases by 20% each year. She figured out that the population would therefore double after five years.

  • What mistake in reasoning about percents did Karen make?
  • Using examples, explain why Karen’s reasoning is incorrect.



What does it mean for a population to “double” in terms of percent? How do you think Karen came up with this percent based on what she read?