Joe, Henry, and Noela, after graduating together, started a business with a $28 000
investment from their parents. For the first two years, they were charged interest at 6%
compounded monthly, but no payments were required during that period. For the next
five years, they would make payments of $625 at the beginning of every month, and the
interest rate would be changed to semi-annual compounding. What is the nominal
interest rate charged for the last five years?