The ability to decide the proportions can be useful in everyday life.
Let's say you have acetic essence with 40% vinegar in your kitchen, and you need 6% vinegar.
Without forming a proportion here can not do.
You will need
- Pen, paper, analytical thinking
We write down the condition of the problem. 40% of the vinegar is 100%, you need to find how much to take the vinegar essence to get 6% vinegar. This will be x. We write down two equations: 40% = 100%, 6% = x.
We get the proportion: 40/6 = 100 / x.
Multiply 6 by 100 and divide by 40.
We get that the acetic essence is 15% of the total water-acetic solution.
That is, you can take 15 ml of acetic essence and 75Ml water to obtain about 100 ml of 6% vinegar. Approximately - because water has the property of substitution, and the output of different solutions can get a little less than originally planned.
The task is more complicated. There is buckwheat flour with a protein content of 12.6 g per 100 g of dry product. And there is a starch with a protein content of 1 g per 100 g of dry product. It is necessary to make a starch-flour mixture with a protein content of 2 g per 100 g of dry product.
We take for x the starch content in the mixture in grams, for (100) the content of buckwheat flour in the mixture in grams.
Then 1 * x / 100 - how many grams of protein is on starch, 12.6 * (100-x) / 100 - how many grams of protein are in buckwheat flour.
In sum, these fractions are 2 g of protein per 100 g of the mixture.
Solving the equation, we get that to obtain a mixture with 2 g of protein we need to take 91 g of starch and 9 g of buckwheat flour.