We will start with Chris's age, since Sue is older than him and Jim is older than Sue. Chris is the youngest. We will say Chris's age is x. If Sue is 2 years older than Chris, Sue is x + 2. Jim is 4 years older than Sue, so Jim is 4 + x + 2, or x + 6. The total of their ages is 68, so x + x + 2 + x + 6 = 68. Simplifying we have 3x + 8 = 68. 3x = 60, so x = 20. Chris is 20, Sue is 22, and Jim is 26. Those numbers do in fact total 68.
