By age 25, an author had already written 8 short stories. Every year since then, she has written 3 more short stories. How do we know that the total number of short stories the author has written is a linear function of the time in years since she was 25 years old? You get one submission.
a. The number of short stories added to her total every year varies, so the growth rate is not constant.
b. The number of short stories added to her total every year is 3, so the growth rate is constant.