Southwest Airlines hedged the cost of jet Fuel by purchasing options that allowed the airline to purchase fuel at a fixed price for 5 years. If the market price of fuel was $0.50 per gallon higher than the option price in year 1, $0.60 per gallon higher in year 2, and amounts increasing by $0.10 per gallon higher through year 5, what was the present worth of SWA's savings per gallon if the interest rate was 10% per year? And can you please tell me how you get the answer?