Recipes and Adjusting Ingredient AmountsDate: 04/20/2005 at 17:00:48 From: Sandie Subject: breaking down a recipe In a recipe, 5 1/2 cups of coconut uses 14 ounces of milk, but I only have 4 cups of coconut, so how many ounces of milk do I use? Date: 04/21/2005 at 11:52:28 From: Doctor Wilko Subject: Re: breaking down a recipe Hi Sandie, Thanks for writing to Dr. Math! I want to give you two different ways to approach this problem. Method One: Think about Ounces per Cup Your recipe says you need to mix 14 oz of milk with 5.5 cups of coconut, right? So my question is, "How many ounces of milk do you mix with one cup of coconut?" Break it down by dividing the 14 ounces by the 5.5 cups: 14 oz ------- is about 2.54 oz of milk per cup of coconut 5.5 c So, if you have four cups of coconut, then you'd mix (2.54 oz of milk per cup of coconut) * (4 c of coconut) = 2.54 * 4 or about 10.16 oz of milk Method Two: Set Up a Proportion You want to keep the ingredients in the same amount relative to each other, or the same ratio. Two equal ratios make a proportion. You can set this up as follows: 14 oz Milk ? oz Milk ----------------- = --------------- 5.5 cups coconut 4 cups coconut In any proportion, if you multiply the top of one ratio times the bottom of the other, you will get the same answer in both directions. So we know that: (14)*(4) = (5.5)*(?) 56 = (5.5)*(?) Divide 56 by 5.5 to see what the (?) must be, just as if you had something like 8 = (4)*(?). 56/5.5 = 10.18 ounces of milk 10.18 oz is approximately equal to 10 oz + 1 Tsp You should mix (10 oz + 1 Tsp) of milk with your four ounces of coconut to keep the recipe in the right proportion! The difference from the answer above (10.16) is due to rounding, but the point is that you need just over 10 oz of milk to keep the same consistency or proportion of the original recipe. If you'd like to see more about proportions, check these links from our archives: Comparing Ratios to Form Proportions http://mathforum.org/library/drmath/view/64554.html Ratios and Proportions in Everyday Life http://mathforum.org/library/drmath/view/60681.html Another way to think about it is, no matter what size recipe you're making or how much coconut you have, if you mix about two and a half ounces of milk for every cup of coconut, you'll keep the recipe in proper proportion. Does this help? Please write back if you have more questions. - Doctor Wilko, The Math Forum http://mathforum.org/dr.math/ |
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