See the attached picture. It is bootstrapping a bond

Table 1: Bond price data for Problem 1.3. The bonds pay coupons every six months. Bond principal Maturity Coupon Bond price 100 100 100 100 TOY 2.25% 3.25% 2.50% 4.25 (70 101.087 C) 3.432 101.168 113.216 Problem 1.3 Bootstrap the zero rate R(T) from prices of the bonds with several maturities in Table 1. All bonds pay coupons every six months. Assume that the zero rate R(T) is piece-wise constant on the time inter- vals between the maturities of the bonds shown. For example R(T) has the same value for all time up to 1 Y, including this maturity, another value for all times from IY to 2 Y, including the latter, and so on.