7. You want to begin an investment plan to save for your son's college education. Because you believe that your newly born son will be a genius (just like you!), you are assuming the cost of an Ivy League education. You plan to put money into an investment account, at the end of each year, for the next 18 years. You believe that you will need about $75,000 per year, each year, 19 through 22 years from now. a) Draw a discrete cash flow diagram for this situation. (5 points) b) How much would you have to invest each year to pay for college and have a zero balance at the end of year 22? The effective annual interest rate of your investment is 8\%. (5 points) c) What interest rate would be needed if you could invest only $5000/y ? (5 points)