a 15-year maturity, 8.75% coupon bond paying coupons semiannually is callable in ten years at a call price of $1,200. The bond curerently sells at a yield to maturity of 7.5% (3.75% per halfyear)....

a 15-year maturity, 8.75% coupon bond paying coupons semiannually is callable in ten years at a call price of $1,200.  The bond curerently sells at a yield to maturity of 7.5% (3.75% per halfyear).

What is the yield to call if the call price is $1,200 but the bond can be called in five years instead of ten?