Answer:
The 2-litter bottle is the better buy because it is less expensive than two of the 1-litter bottles of soda.
Explanation:
You know that a 1-litter bottle of soda cost $0.99. So, if you want to buy 2 liters of soda you can perform the following calculation:
2 bottles of a 1-litter bottle of soda * price of a 1-litter bottle of soda
2*$0.99= $1.98
So, if you want to buy 2 liters of soda by acquiring 2 1-litter bottle of soda, you must pay $ 1.98.
On the other side, you know that a 2-litter bottle of soda costs $1.59.
Comparing, you can see that the price of 2 1-liter bottles is more expensive than the price of a 2-liter bottle, with a difference of:
$1.98 - $1.59= $0.39
In others words, the 2-litter bottle is the better buy because it is less expensive than two of the 1-litter bottles of soda.