A 20-year maturity, 7.6% coupon bond paying coupons semiannually is callable in seven years at a call price of $1,170. The bond currently sells at a yield to maturity of 6.6% (3.30% per half-year).

What is the yield to call?

What is the yield to call if the call price is only $1,120?

What is the yield to call if the call price is $1,170 but the bond can be called in four years instead of seven years?