Stan Money maker needs 16 gallons of gas to top off his tank. I he drives an extra 8 mile round trip Stan can save an extra $0.05 a gallon. Suppose gas costs $3.10 per gallon and Stan gets 24mpg. Each mile driven gives off CO2 that has an environmental impact cost of $0.02. What are Stan's savings per mile on making the 8 mile extra trip, including the environmental impact cost?