Lisa paid $48.95 for 15.1 gallons of gasoline. What was the cost of gas rounded to the nearest hundredth?

3.24 dollars per gallon

You are looking for the cost of gas per gallon in this problem so you must use an equation where you do cost in dollars / barrels. Therefore you must do $48.95/15.1 gallons of gasoline which equals $3.242 per gallon of gas.