1. Considering a corporate tax rate of 20%, compute the present value of interest tax shields generated by the following types of debt:

1. 100,000 10-year loan with maturity in 10 years and interest rate of 6%. Debt is to be paid 20% in 2 years, 30% in 7 years and the remaining at maturity.
2. Perpetual bond (zero-coupon) with an implied yield of 5%.
3. 5-year loan with maturity in 5 years, interest rate of 5% and constant annual payments.