The initial situation is that the odometer read 49,420 miles. Since the odometer is the indication of the total distance traveled by the car, we should subtract the initial odometer reading from the final odometer reading (49,717 miles) to get the distance traveled by the car after the refill, and before or during the next refill. Tammys car traveled a total of 297 mi according to the initial and final odometer readings.
The next thing to do would be to divide the number of miles traveled by the car by the volume of gas used up to cover such distance to get the miles to the gallon that Tammys car achieved:B. If it took 15 gallons of gas to fill the tank, how many miles to the gallon did Tammys car achieve? Since we already have the distance traveled by the car, we can now divide it to the number of gallons used up to travel such a distance: