In previous math courses, you’ve no doubt run into the infamous “word problems.”  Unfortunately, these problems rarely resemble the type of problems we actually encounter in everyday life.  In math books, you usually are told exactly which formula or procedure to use, and are given exactly the information you need to answer the question.  In real life, problem solving requires identifying an appropriate formula or procedure, and determining what information you will need (and won’t need) to answer the question.  In this chapter, we will review several basic but powerful algebraic ideas:  percents, rates, and proportions.  We will then focus on the problem solving process, and explore how to use these ideas to solve problems where we don’t have perfect information.