Answer :
Answer:
5.10%
Explanation
Since coupons are paid semi-annually, adjust the time and coupon payment amount to semiannual basis.
Face value of the bond ; FV = 1,000
Maturity of the bond ; N = 30*2 = 60
Price of the bond; PV = - ( 1.031 * 1000) = -1,031
Semi-annual coupon payment; PMT = (8%/2)*1,000 = 40
Then compute semiannual interest rate ; CPT I/Y = 3.866%
Next, convert the 3.866% to annual rate (YTM) = 3.866% * 2 = 7.732%
Therefore, pretax cost of debt is 7.732%
Aftertax cost of debt = pretax cost of debt (1-tax)
= 0.07732(1-0.34)
= 0.0510 or 5.10%