Looking at an imaginary ice cream's nutrition facts table, say I see the following information:
- Per Serving Size: 100ml
- Calories Per Serving: 250
- Calories Per 100 Grams: 500
What's the formula to compute the milliliters in 100 grams?
Intuitively, the answer is 200 ml: 100ml = 250 calories, therefore 200ml = 500 calories -- and that's 100 grams). I'm just not sure how to express this in a proper formula.
You can do something like this:
Let's say that the answer is $x$ milliliters. Then you would have $\frac{x}{100}$ servings from the first bullet point. From that, you can multiply $250$ to find the total amount of calories: $\frac{x}{100}*250=\frac{5x}2$ total calories. Then set up a proportion like this(from third bullet point):$$\frac{500\ \text{Calories}}{100\ \text{grams}}=\frac{5x/2}{100\text{ grams}}$$Which simplifies to $\frac{5x}2=500\implies x=200\ \text{ml}$
I'm not sure if this is the "formulaic" way that you wanted, but it is certainly systematic. This sure overcomplicates the problem though(you can solve this problem in your head without variables).