4 liters (2 bottles)-.215 = 1 gallon, 3.785.
4 liters-.215 = 1 gallon 3.785
so 2 gallons is equal to 7.57 liters. Now i add both the .215 together and get .43 then add the .43 to the 7.57 liters and get 8 liters. 8 liters is equal to 4 bottles of soda. Now i add the 2 liters from the last bottle to the 8 liters and get 10. then i divide that by 3.785 and get 2.642 gallons.
MORE SIMPLE WAY TO SOLVE: multiply the 5 bottles by the 2 liters and get 10 liters then divide by 3.785 to get 2.642