Answer:
If we were interested in how the gas prices had changed between 2002 and 2009, we could compute that the cost per gallon had increased from $1.47 to $2.14, an increase of $0.67. While this is interesting, it might be more useful to look at how much the price changed per year. You are probably noticing that the price didn’t change the same amount each year, so we would be finding the average rate of change over a specified amount of time.
The gas price increased by $0.67 from 2002 to 2009, over 7 years, for an average of
$0.677yearsapprox0.096
dollars per year. On average, the price of gas increased by about 9.6 cents each year.
hope it helps
