Expert: Steve Holleran - 5/23/2008

Question
Examine the rise in gasoline prices from 1997 to 2006. The price of regular unleaded gasoline in January 1997 was $1.26 and in January 2006 the price of regular unleaded gasoline was $2.31 (Bureau of Labor Statistics, 2006). Use the coordinates (1997, 1.26) and (2006, 2.31) to find the slope (or rate of change) between the two points. Describe how you arrived at your answer.

Answer
Hi Kizzy,

Slope, or rate of change, is simply a division.

Here, you want to divide the change in the price, 2.31 - 1.26 = 1.05

by the change in time, 9 years:

   1.05 / 9 = 0.1167.  This means that on average, the price rose

11.67 cents per year.

Steve