Answer
Gasoline: 62.5 dollars
E85: 63.3 dollars
Work Step by Step
Gasoline: $$500. \text{ miles}*\frac{1 \text{ gallon}}{28 \text{ miles}}*\frac{3.50 \text{ dollars}}{1 \text{ gallon}}=62.5 \text{ dollars}$$
E85: $$500. \text{ miles}*\frac{1 \text{ gallon}}{22.5 \text{ miles}}*\frac{2.85 \text{ dollars}}{1 \text{ gallon}}=63.3 \text{ dollars}$$
