x) A Southern Georgia school district is considering ordering 53 propane-fueled buses. "They're healthier, they're cleaner burning. and they're much quieter than the diesel option," said a school administrator. Propane-powered buses also reduce greenhouse gasses by 22% compared to gasoline-powered buses and 6% compared to diesel ones. But they come at a premium; that is, 5103,000 for a propane model, $15,000 more than the diesel equivalent The propane bus operating cost (above and beyond fuel cost) is 30 cents/mile, compare to 40 cents/mile for the diesel. Diesel fuel costs about $2/gallon in Georgia, about $1 more than propane. Bus mileage is 12 mpg for the propane model vs. 10 mpg for diesel. The life of a school bus in the district averages 9 years, and each bus travels an average of 30,000 miles per year because the district is so large and rural. a) Which bus is the better choice based on a life cycle analysis? (10 points) b) What is the cross-over point in miles? What is that in years? (10 points)