Chapter 1.2, Problem 6E

Freight on Class I Railroads According to the Association of American Railroads, Class I freight railroads are the line-haul freight railroads with $2006$ operating revenue in excess of $\$346.8\text{million}$. Let $F=F\left(t\right)$ denote the freight revenue in billions of dollars of Class I railroads in year $t$. In $2005$, Class I railroads had a freight revenue of $\$44.5\text{billion}$. In $2007$, the revenue was $\$52.9$ billion. Calculate the average rate of change per year in $F$ from $2005$ to $2007$ and explain its meaning in practical terms.