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 million. let f = f(t) 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 billion. in 2007, the revenue was $52.9 billion. calculate the average rate of change per year in f from 2005 to 2007.

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 and , then the formula for rate of change is

The average rate of change per year in F from 2005 to 2007 is

Therefore the average rate of change per year in F from 2005 to 2007 is $4.2 billion/year.