For each of the following $1,000-par-value bonds, assuming annual interest payment and a 40% tax rate, calculate the after-tax cost to maturity using the approximation formula.
Bond Life Underwriting fee Discount (-) or premium (+) Coupon interest rate
A 20 $25 -$20 9%
B 16 40 +10 10
C 15 30 -15 12
D 25 15 Par 9
E 22 20 -60 11