Let's first answer what would be the cost of gasoline for each route.
The car needs 18 gallons of gasoline for every 296 miles. So the cars efficiency is
[tex]\frac{396\text{ mi}}{18\text{ gal}}\text{ =}22\text{ mi/gal}[/tex]The southern route has 3102 miles long with an average cost of 2.20 dollars. Then the cost for the southern route is
[tex]3102\text{ mi }\times\frac{1\text{ gal}}{22\text{ mi}}\text{ }\times2.20\text{ dlls = 3}10.20\text{ dlls}[/tex]The cost for the southern route is 310.20 dlls.
The northern route is 2918 mi and the average cost is 2.28 dlls. Then the cost for this route is
[tex]2918\text{ mi}\times\frac{1\text{ gal}}{22\text{ mi}}\times2.28\text{ dlls = }302.41\text{ dlls}[/tex]he cost for the southern route is 302.41 dlls.