Calculate the future value after 25 years in each of the following scenarios:

a. $6000 is invested at the end of each year earning 6% compounded annually.

b. $3000 is invested at the end of each half-year earning 6% compounded semiannually.

c. $1500 is invested at the end of each quarter earning 6% compounded quarterly.

d. $500 is invested at the end of each month earning 6% compounded monthly.

Note that the same total amount ($6000) is invested each year and that the nominal interest rate (6%) is the same in each case. The combined beneficial effects of (i) smaller but earlier more frequent payments, and (ii) more frequent compounding are quite significant.