Question $1$:

A $30-$year maturity, $7\mathrm{.}8\%$ coupon bond paying coupons semiannually is callable in five years at a call price of $$1,160.$ The bond currently sells at a yield to maturity of $6\mathrm{.}8\%(3\mathrm{.}40\%$ per half$-$year$).$ The yield to call is $\_\_\_\_\_\_\%.$