Brads portfolio consists of three bonds:

a 10-year zero-coupon bond with a redemption value of $100,000, a 15-year coupon bond with Macaulay duration of 10.9994 and price of $33,114.06, and

a 20-year par bond with the redemption of $50,000 and an annual coupon rate of 4.00%.

All prices and durations were calculated assuming an annual yield of 4.25%. The first-order Macaulay approximation of the price of this portfolio, when the interest rate fell to i, is $150,710.00. Find the following.

a) The price of the portfolio at the original rate of i₀ = 4.25%.

b) The Macaulay duration of the portfolio.

c) The new interest rate i, written as a percentage.