Final answer:
A Tesla does not use gallons of fuel, so we cannot convert miles to gallons in this case.
Step-by-step explanation:
To determine the number of gallons it would take to travel 390 miles in a Tesla, we need to know the fuel efficiency of the car. However, Teslas run on electricity, not gasoline, so they do not use gallons of fuel. Instead, they use kilowatt-hours (kWh) of electricity. So, we cannot convert miles to gallons in this case.