Your grandfather put some money in an account for you on the day you were born. You are now 18 years old and are allowed to withdraw the money for the first time. The account currently has $15,000 in it and pays a 2.5% interest rate.

a. How much money would be in the account if you left the money there until your 40th birthday?

b. What if you left the money until your 65th birthday?

c. How much money did your grandfather originally put in the account?