on january 1, a company issued 10%, 20-year bonds with a face amount of $80 million for $73,581,280 to yield 11%. interest is paid semiannually. what was interest expense at the effective interest rate on june 30, the first interest date? (enter your answers in whole dollars. round percentage answers to 1 decimal place (e.g., 0.0234 should be entered as 2.3).)