Technically you're only supposed to use the top ingredient on the list as free food, which is tomato, so counting that as free it comes out at 3 syns per 100g or 10 syns per pack
Personally as the pasta content is so close to the same amount as the tomato I would 'tweak' it and count that as the free ingredient, which makes it 1½ syns per 100g or 5½ Syn per pack
Whether you want to tweak or follow the rules to the letter is up to you