1. **Problem:** The cooks made 120 quarts, 150 quarts, and 130 quarts of lemonade for three concerts respectively. How many gallons of lemonade did they make in total? 2. **Formula:** 1 gallon = 4 quarts. 3. **Step 1:** Add the quarts of lemonade made for all three concerts: $$120 + 150 + 130 = 400 \text{ quarts}$$ 4. **Step 2:** Convert quarts to gallons using the conversion factor: $$\text{gallons} = \frac{400}{4}$$ 5. **Step 3:** Show cancellation of common factor: $$\frac{\cancel{400}}{\cancel{4}} = 100$$ 6. **Answer:** The cooks made **100 gallons** of lemonade in all.