Jean has decided it is time to buy a new battery for her car. Her choices are: First cost Guaranteed period Zappo $48 12 Kicko $78 24 Jean believes the batteries can be expected to last only for a guaranteed period. She does not want to invest extra money in a battery unless she can expect a 40% rate of return. If she plans to keep her present car for another 2 years, which battery should she buy?