The duration a 300-gallon gas tank will last depends on several factors, including the vehicle's fuel efficiency, driving conditions, and the speed at which the vehicle is driven. On average, a car with a fuel efficiency of 20 miles per gallon (mpg) can expect to travel approximately 6,000 miles on a full 300-gallon tank. This calculation assumes consistent driving conditions and speed, with no significant changes in terrain or traffic patterns.

The fuel efficiency of a vehicle is a critical factor in determining how long a 300-gallon gas tank will last. For instance, a car with a fuel efficiency of 30 mpg will travel approximately 9,000 miles on the same tank, while a vehicle with a fuel efficiency of 15 mpg will cover about 4,000 miles. The speed at which the vehicle is driven also plays a role; idling in traffic or driving at high speeds can significantly reduce fuel efficiency.

Data from the U.S. Department of Energy's Fuel Economy website provides insights into the average fuel efficiency of vehicles. According to the 2021 data, the average fuel efficiency for all vehicles in the United States is approximately 25 mpg. This means that a 300-gallon gas tank would typically last around 7,500 miles under average driving conditions.

However, it's important to note that real-world fuel efficiency can vary significantly from the manufacturer's estimates. Factors such as driving habits, vehicle maintenance, and weather conditions can all impact fuel efficiency. For example, a driver who frequently drives in stop-and-go traffic or carries heavy loads may experience lower fuel efficiency than the manufacturer's estimate.

In conclusion, the duration a 300-gallon gas tank will last largely depends on the vehicle's fuel efficiency and driving conditions. On average, a car with a fuel efficiency of 25 mpg can expect to travel around 7,500 miles on a full tank. It's essential for drivers to consider their specific driving habits and vehicle characteristics when estimating fuel consumption and planning trips.