What is the term structure of interest rates (r1, r2, r3), given the following bonds: a 3-year coupon bond with face value of $1000 and annual coupon rate of 15%, currently traded at $1300.63 a 3-year coupon bond with face value of $1000 and annual coupon rate of 6%, currently traded at $1050.58 a 2-year coupon bond with face value of $1000 and annual coupon rate of 10%, currently traded at $1115.78