[tex]\begin{gathered} \text{Car A travels 308 miles on 11 gallons, so, the ratio of miles per galon is} \\ \frac{308}{11}=28\text{ miles per gallon} \\ \\ \text{for the car B, the ratio is} \\ \frac{406}{14}=29\text{ miles per gallon} \end{gathered}[/tex]
thus, the best car is car B,because it can tavel 29 miles with only one gallon,andcar A can only travel 28 miles with one gallon.