Shanken corp. issued a 20-year, 4.6 percent semiannual bond 4 years ago. the bond currently sells for 93 percent of its face value. the company's tax rate is 21 percent. a. what is the pretax cost of debt? (do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e. g., 32.16.) b. what is the aftertax cost of debt? (do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e. g., 32.16.)