Cost of debt of irredeemable debt

The after-tax cost.

Sir If question says that A ltd has 3% debentures at a par value of $100. Debt can be redeemed at Par after 4 years or converted after 4 years into 10 shares at $8 per share. Tax rate is 20%, cost of debt is 15%. Calculate market value of debenture? Here cost of debt of 15% is before tax cost of debt OR after tax cost of debt? Sir If question says that A ltd has 3% debentures at a par value of $100. Debt can be redeemed at Par after 4 years or converted after 4 years into 10 shares at $8 per share. Tax rate is 20%,debt holders required return is 15%. Calculate market value of debenture? Here debt holders required return of 15% is before tax cost of debt OR after tax cost of debt?

Assuming you have copied the questions word for word, then for the first one the 15% is after tax and for the second one the 15% is before tax. I don't know why you are asking me, since it must be clear from the answers what has been done, and you say that you have watched my lectures.