Answer:
The average rate of change per year in F from 2005 to 2007 is $4.2 billion/year.
Explanation:
Let F = F(t),
It represents freight revenue in billions of dollars of Class I railroads in year t.
It is given that in 2005, Class I railroads had a freight revenue of $44.5 billion. In 2007, the revenue was $52.9 billion.
f(2005)=$44.5
f(2007)=$52.9
If a linear function passes through two points [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex], then the formula for rate of change is
[tex]m=\frac{f(x_2)-f(x_1)}{x_2-x_1}[/tex]
The average rate of change per year in F from 2005 to 2007 is
[tex]m=\frac{f(2007)-f(2005)}{2007-2005}[/tex]
[tex]m=\frac{52.9-44.5}{2}[/tex]
[tex]m=\frac{8.4}{2}[/tex]
[tex]m=4.2[/tex]
Therefore the average rate of change per year in F from 2005 to 2007 is $4.2 billion/year.
