To convert gallons to liters, you can use the conversion factor that there are approximately 3.8 liters in 1 gallon.
To find out how many liters are in 15.4 gallons, you can use the following calculation:
\[ \text{liters} = \text{gallons} \times \text{liters per gallon} \]
Substituting in the values:
\[ \text{liters} = 15.4 \text{ gallons} \times 3.8 \text{ liters/gallon} \]
Calculating this gives:
\[ \text{liters} = 15.4 \times 3.8 = 58.52 \text{ liters} \]
So, Julie bought approximately 58.52 liters of gasoline.