henry opened a savings account and deposited $800. The account earns 3% interest compounded semiannually. What is the balance after 6 years?

The balance in Henry's account after 6 years will be =$956.49.

The formula you would use here is this: FV=PV[1 + R ]^N, Where R=Interest rate per period, N=number of periods, PV=Present value, FV=Future value.