F) Graph the two equations in Case II to confirm your result in part (e). ABOVE 5-55. Additional Challenge: At the beginning of 1990, oil prices were $20 a barrel.
Some oil investors predicted that the price of oil would increase by $2.25 a barrel per
year. In the beginning of 2005, the price of oil was $30 a barrel. With increasing
demand for oil around the world, oil investors in 2005 predicted that the price of oil
would increase by $5.00 a barrel each year.
a) Let x represent the number of years since 2005. Write an equation that predicts
the price of oil, y, using the information available in 2005.
b) Investors in 1990 did not have the benefit of the 2005 information. Write an
equation that represents the prediction made in 1990, using the same variables as in
part (a). Use x + 15 since it is an extra 15 years since 1990.
c) Use the equations you wrote in parts (a) and (b) to determine when the cost of a
barrel of oil would be the same for both price predictions.