Charlie is preparing plates of seafood salad for the lunchtime menu. She will put 50 grams of each of prawns, cockles, whelks, squid, and smoked salmon on each plate. The prawns are available in 400 gram packs, the cockles, the whelks and the smoked salmon are available in 200 gram packs, and the squid is available in 300 gram packs. All packs of each seafood item cost €4.08, but the wholesaler offers a deal of ‘buy any two packs of one item and get another pack of the same item free’.