1. The problem states that for every 2 flavor packages, 300 ml of sugar is needed. 2. We want to find an equation relating $s$, the amount of sugar in milliliters, to $f$, the number of flavor packages. 3. Since 300 ml corresponds to 2 flavor packages, the ratio of sugar to flavor packages is $\frac{300}{2} = 150$ ml per flavor package. 4. Therefore, the amount of sugar $s$ is proportional to the number of flavor packages $f$ by the equation: $$s = 150f$$ This equation shows that for each flavor package, 150 ml of sugar is required. Final answer: $$s = 150f$$