Читать книгу SAT Math For Dummies with Online Practice - Mark Zegarelli - Страница 48

Once you understand how fractions work, you can easily grasp the related concept of a ratio, which is a measurement of the relative sizes of two numbers. For example, if you know that a pet store has a (or 1-to-3) ratio of dogs to cats, you know that the number of dogs is the number of cats.

Transforming a ratio to its related fraction in this way is often a good first step when answering SAT questions that involve ratios.

I discuss ratios, plus the related concept of proportional equations, in Chapter 7.