The market price is $850 for a 20-year bond ($1,000 par value) that pays 12 percent annual interest, but makes interest payments on a semiannual…

The market price is ​$850 for a 20​-year bond ​($1,000 par​ value) that pays 12 percent annual​ interest, but makes interest payments on a semiannual basis ​(6 percent​ semiannually). What is the​ bond’s yield to​ maturity?