First write an equation system based on the problem We can write "Bread and sugar cost 110 together" as ∴ b + s = 110 We can write "bread cost 100 more than sugar" as ∴ b = 100 + s Second, solve the equation system by subtitution method Subtitute b with (100+s) in the first equation, and we'll find the value of s b + s = 110 (100 + s) + s = 110 100 + 2s = 110 2s = 110 - 100 2s = 10 s = 10/2 s = 5 The cost of the sugar is 5
