A student is spending five years at college and at the beginning of each college year she is taking an annual student debt of $18,000. The annual interest rate on student debt is 7.5%. 1) What is the total amount of student debt at graduation? 2) If annual income after college is $50,000 and the newly minted graduate budgets 20 percent of his annual income toward payments on college debt, how long will it take to pay off the entire debt when the annual interest rate on it is 7.5%? 3) If annual income after college is $50,000 and the newly minted graduate budgets 15 percent of his annual income toward payments on college debt, how long will it take to pay off the entire debt when the annual interest rate on it is 7.5%? 4) If annual income after college is $50,000 and the annual interest rate on debt is 7.5%, what percentage of annual post-college income should go toward payments on student debt to have it fully paid off in 9 years? 5) Bob starts going to college at the age of 18. He will spend five years at college and at the beginning of each college year he is to pay $18,000. If the annual savings rate is 7.5%, how much do his parents have to save annually at the end of each year until Bob enters the college so that he does not have to take on any debt during his college years?