There are several methods we can use to compare two quantities. This section of Dralgebra.com will introduce the concept of a ratio. A ratio can be thought of as a way to express how a mixture is made up.
For example, a recipe for bread might call for two cups of flour, a half cup of water, and one cup of sugar. If we want to double the amount of bread, we would just double the amount of each ingredient and the same method could be used to make only half the amount of bread.
Ratio’s can be written several different ways. Let’s see these in action…
Say I have a basket with 3 apples and 5 oranges. I want to show how many apples I have compared to oranges so that when I make juice, I can always make it the same. There are four common ways to write this down as a ratio and all four ways of writing the ratio of apples to oranges are equivalent.
| Standard style: | [katex]3:5[/katex] |
| Fraction style: | [katex]\frac{3}{5}[/katex] |
| Verbal style: | 3 apples to 5 oranges (or just say 3 to 5) |
| Tape style: |  |
Now that we know how to write ratio’s, the question is what to do with them. Ratio’s provide an easy way multiply or divide several quantities in the same way.