Question

A daily newspaper had 12,125 subscribers when it began publication. Five years later it had 10,100 subscribers. What is the average yearly rate of change in the number of subscribers for the five-year period?

Answer 1

`405` readers lost per year.

Explanation:

The newspaper lost `12125-10100=2025` readers in a `5` year span. If we want to compute the average, we must assume that this loss was constant. If the newspaper lost readers with a constant rate, and it lost `2025` readers in `5` years, it means that every year it lost `2025=5 = 405` readers.

As another example, think of this: if I told you that I had to travel from a city to another, and I did `600` km in `6` hour, how many km do you think I did per hour? `100` of course. But this is just an average, because I could have done the first `500` km in a hour and then spent `5` hours for the last `100` km.