(Yield to maturity) A bond's market price is $750.

​(Yield to​ maturity) A​ bond's market price is ​$750. It has a ​$1,000 par​ value, will mature in 8 ​years, and has a coupon interest rate of 9 percent annual​ interest, but makes its interest payments semiannually. What is the​ bond's yield to​ maturity? What happens to the​ bond's yield to maturity if the bond matures in 16 ​years? What if it matures in 4 ​years?