Final answer:
Grace's car can travel 1.1 miles farther on one gallon of gas than Mila's car. This is calculated using Grace's fuel efficiency equation and Mila's miles per gallon figure.
Step-by-step explanation:
The question asks to compare the fuel efficiency of two cars belonging to two friends, Grace and Mila, both of whom have just bought their first cars. Grace's car's fuel efficiency is defined by the equation y = 38.2c, where y is the number of miles she can drive on c gallons of gas. We know Mila can drive 222.6 miles using 6 gallons of gas. To compare, first, we calculate Mila's miles per gallon by dividing 222.6 miles by 6 gallons, which gives 37.1 miles per gallon.
Next, to find out how far Grace's car can travel on one gallon of gas, we substitute c with 1 in Grace's equation, yielding y = 38.2 miles per gallon. Now, to determine how much farther Grace's car can travel on one gallon of gas compared to Mila's car, we simply subtract Mila's miles per gallon (37.1) from Grace's (38.2), which results in 1.1 miles. Hence, Grace's car can travel 1.1 miles farther on one gallon of gas than Mila's car.