You are managing a portfolio of $1 million. Your target duration is 10 years, and you can invest in two bonds, a zero-coupon bond with maturity of five years and a perpetuity, each currently yielding 6.6%. a. What weight of each bond will you hold to immunize your portfolio? (Round your answers to 2 decimal places.) b. How will these weights change next year if target duration is now nine years? (Round your answers to 2 decimal places.)