Answer:
a. 9.64%
b. 7.71%
Step-by-step explanation:
For this question, we use the RATE formula that is shown in attachment
Given that,
Present value = $960
Future value or Face value = $1,000
PMT = $90
NPER = 10 years
The formula is shown below:
= Rate(NPER;PMT;-PV;FV;type)
The present value come in negative
So, after solving this,
a. The pretax cost of debt is 9.64%
b. And, the after tax cost of debt would be
= Pretax cost of debt × ( 1 - tax rate)
= 9.64% × ( 1 - 0.20)
= 7.71%