The rates are nominal semiannual rates, as well as doling out semiannual coupons and face value at maturity.

2) A 30 year bond with $10.000 face value offers a coupon rate of 6% and a yield rate of 10%. Suppose you pay taxes immediately after receiving each coupon) of 5% of the full coupon amount, and pay a 10% tax immediately after the face value is received on the amount of discount that the bond was purchased at. Find the actual yield (as a semiannual rate for the 30 year period