Problem $3$: The duration of a portfolio of bonds is just the weighted average of the durations of the

bonds in the portfolio, where the weight on a particular bond is the fraction of the value of the portfolio

that comes from that particular bond; the weight sum to $1.$ Consider the following information on $4$

bonds:

Consider the following three portfolios $($the portfolios differ by the amount of current value in each

bond$)$; the data below shows the current values in each of the bonds for each of the portfolios.

Which of these three portfolios has the most interest rate risk?