Part One
The cost of 2 liters is $2.40
The cost of 1 liter = 2.40/2 = 1.20
Part two
1 bottle contains 12 liters
6 bottles contain 12*6 = 72 liters.
All of this comes at a cost of 3.90
The cost is 3.90 / 72 = 0.054 dollars / Liter which is about 5 pennies.
The one with the higher cost is 1.40 dollars / liter. Part One. Answer