you are the cfo of a bond fund. the duration of your liabilities is 5 years. your task is to decide on an optimal portfolio of short term and long term bonds that will immunize your interest rate risk. more precisely, we want the fraction of your bond portfolio that will be 30-year maturity long-term bonds and the fraction that will be in 3-year maturity short-term bonds? the duration of the long-term bond is 20 years and the duration of the short-term bond is 2 years. what fraction of your portfolio is in short-term bonds? provide you answer to rounded to 2 decimal places