Answer:
7.28%
Step-by-step explanation:
Coupon rate = 8%
Nper = 10 (25-15)
PMT = 80 (1000*8%)
FV = 1000
PV = 1050
Yield to maturity = Rate(Nper, pmt, -pv, fv)
Yield to maturity = Rate(10. 80, -1050, 1000)
Yield to maturity = 0.072789069
Yield to maturity = 7.28%
Thus, the pretax cost of debt is 7.28%.