a shopper needs 24 sandwich rolls the store sells identical rolls and two differently sized packages they sell a six pack for $5.28 and four packs for $3.40 should the Shopper by for six packs or four four packs

I think six packs because it only takes 5 bags of the six pack to get 26 but it takes 7 packs of the four packs to only get 23 and 8 packs of the four pack to get 27 it's a better deal to get the 5 packs of the $5.28 pack