Assume the average starting income of a high school graduate is $40,000 per year for four years and the cost of going to college is $45,000 per year for four years. Also, assume that after graduating from college people work for 40 years. On average, what is the MINIMUM a college grad would need to make over and above a high school grad to at least justify the cost of going to college. (Ignore any other concepts like interest rates, present value and risk, etc., which may be covered later.)