6 pack of pepsi is $1.80
12 divided by 6 is 2.
1.80 x 2 is 3.60
If you buy two of the 6 pack pepsis, it would have 12 pack of pepsi but would cost $3.60. If you buy the 12 pack, it would be $3.50 so it would be the 12 packs being the better deal.
*note* I'm stupid so I would probably buy the 6 packs twice ;(