Alice Larsen wanted to see if a new premium gasoline would give her more kilometers to the liter.
She filled her car with the new gas and went on a long trip.
When she figured her mileage, she discovered that she has gone 40 Km farther on this tank of gas than she went on a tanks of old gas when she was driving around town as before.
She decided to buy the premium gas to get better distance.
She did something wrong, tell me the major error from her experiment.