PlusUltra has issued A\% quarterly coupon bonds at a Face Value of \$B. These bonds are selling in the market at \$C per bond and have D years till maturity. Given PlusUltra's aftertax cost of debt is E%, find the marginal tax rate \begin{tabular}{lr} A & 12% \\ B & 1000 \\ C & 300 \\ I & 7 \\ I & 3.6% \end{tabular}