1. **Problem statement:** Calculate the car's average miles-per-gallon (mpg) for the entire trip. 2. **Given data:** - Initial odometer reading: 56,200 miles - Gas tank initially has 6 gallons - Driver refilled 12 gallons at odometer 56,560 - Driver refilled 20 gallons at odometer 57,060 3. **Step 1: Calculate total miles driven.** $$\text{Total miles} = 57,060 - 56,200 = 860$$ 4. **Step 2: Calculate total gallons used.** The driver started with 6 gallons, then added 12 gallons, then 20 gallons. $$\text{Total gallons} = 6 + 12 + 20 = 38$$ 5. **Step 3: Calculate average miles per gallon.** $$\text{Average mpg} = \frac{\text{Total miles}}{\text{Total gallons}} = \frac{860}{38}$$ 6. **Step 4: Simplify the fraction.** $$\frac{860}{38} = \frac{\cancel{2} \times 430}{\cancel{2} \times 19} = \frac{430}{19}$$ 7. **Step 5: Calculate decimal value.** $$\frac{430}{19} \approx 22.6315$$ 8. **Step 6: Round to the nearest tenth.** $$22.6$$ **Final answer:** The car's average miles-per-gallon for the entire trip is approximately **22.6 mpg**.