Mark must buy four new tires for his car. he is considering buying tires that are $25 a piece more than his regular brand, because the higher priced tires are supposed to increase his miles per gallon by 20%. if the tires are good for 48000 miles and mark drives an average of 1000 miles per month, gas cost $2.50 per gallon over the next 4 years, and mark's car gets 30 miles to the gallon now(old tires) should mark purchase the more expensive tires? show me how you got the answer