Question

Roger’s brother gave Roger his collection of coins when he left for college. At that time, the value of the collection was $720. Twelve years later, the collection was worth $1080. What is the rate of change? Don't forget your units.

Answer 1

A: The rate of change is 10% per year.

Explanation:

The rate of change is simply the change in value divided by the change in time. In this case, the change in value is $1080 - $720 = $360, and the change in time is 12 years. Therefore, the rate of change is $360 / 12 years = $30 per year.