8.2.3 Ratios in Recipes
[ Feeling a little shaky with ratios written in colon notation? Check out this interactive website. ] So far, you have worked with ratios as fractions. Remember that ratios are also given in colon notation. For example, a recipe may call for two cups of raisins for every three cups of oatmeal. This can be written as the ratio 2:3. If you decided to make more or less of recipe, you need to preserve the ratio. In other words, there would need to be two parts raisins for every three parts oatmeal. Let’s look at an example.
A recipe for shortbread requires 12 ounces of all purpose flour, 4 ounces of sugar and 8 ounces of butter.
This means that the ratio of flour to sugar to butter is 12:4:8. Ratios can be canceled down like fractions. Dividing all parts of the ratio by 4, it can be expressed more simply as 3:1:2 or three parts flour, one part sugar and two parts butter.
Suppose you wish to make some shortbread following this recipe using 12 ounces of butter, how much flour and sugar will you need?
Start with the butter, 12 ounces is equivalent to two parts.
So one part is the same as .
Hence, three parts will be the same as .
So, 18 ounces of flour and 6 ounces of sugar will be needed.