1. **State the problem:** We know that 2 cookies weigh 30.30 grams in total, and each cookie weighs 15.15 grams. We want to find how much sugar is used in 7 cookies. 2. **Identify the formula:** Since the weight of sugar is proportional to the number of cookies, we use the formula: $$\text{Total sugar} = \text{weight per cookie} \times \text{number of cookies}$$ 3. **Given values:** - Weight per cookie = 15.15 grams - Number of cookies = 7 4. **Calculate the total sugar for 7 cookies:** $$15.15 \times 7 = 106.05$$ 5. **Interpretation:** The total sugar used in 7 cookies is 106.05 grams. **Final answer:** $$\boxed{106.05 \text{ grams}}$$