could you please do the math step by step without Excel and showing the steps. instant like if so. thank you:)

1. Shanken Corp. issued a 30 -year, 6.2 percent semiannual bond 7 years ago. The bond currently sells for 108 percent of its face value. The company's tax rate is 35 percent. (Assume that the face value of one coupon bond is $1,000.) a. What is the pretax cost of debt? b. What is the aftertax cost of debt? c. Which is more relevant, the pretax or the aftertax cost of debt? Why