It is deemed that your niece, Maira (who is four years old), will be going to a four-year college that will cost her no more than $20,000 a year. If Grandpa will buy today as a one-time purchase, saving Bonds at 8% interest for Maira, what dollar amount should he buy to make sure she has $80,000 at the start of college? College education is expected to start when Maira will be 18 years old.