You have $10,000 to invest for the next 40 years for your retirement. You are offered an investment plan that will pay you 5% per year for the next 20 years and 10% for the last 20 years. How much will you end up with in 40 years' time? Does it matter if the investment plan pay you 10% for the first 20 years and 5% for the next 20 years? Why or why not?