Shop Smart: 24 pack, but you get 2 for 9$. So (24 x 2) / 9 = 48/9 = $5.33
Super Saver: 12 pack, but you get 4 for 10$. So (12 x 4) / 10 = 48 / 10 = $4.8
Price Busters: 12 pack, but you get 3 for 9$. So (12 x 3 ) / 9 = 36 / 9 = $4
You want to get the total number of cans and divide it by the total price, to work out the price per can.
For B.) You'll want to select the cheapest lemonade, which is sold in Price Buster