Simple Corp. has one bond issue oustanding, with a maturity of $10\mathrm{.}5$ years, a coupon rate of $3\%$ and a yield to maturity of $4\mathrm{.}5\%.$

Simple Corp.$\text{'}$s average tax rate is $18\%$ and its marginal tax rate is $31\%.$

QUESTION$/$ PART ONE: What is the $($pre$-$tax$)$ cost of debt?

Q$2$: What is the after$-$tax cost of debt?