In 1984 the Fizzy Cola Company sold 23 million gallons of soda By 2003 the company was selling 127 million gallons of soda What is the average rate of change in the number of gallons of soda per year?

First, you need to find the change in the number of gallons of soda sold during the given time interval. So:

(Final gallons) - (Initial gallons) = (127 gallons) - (23 gallons) = 104 gallons

Next, you need to determine how much time has elapsed between the two given years. So:

(Final year) - (Initial year) = (2003) - (1984) = 19 years

Since you are looking for number of gallons of soda per year, your equation is:

(Change in number of gallons sold)/(Time elapsed) = (104 gallons)/(19 years) = 5.473684211 gallons per year = 5.47 gallons per year