5 packages would be 13.75 because by dividing 11 (the cost) and 4 (amount) you get the cost of one package. That would be 2.75. After you have the cost of one you multiply it by 5 and that’s 13.75
2.2 u divide 11 by 4 to get a answer of 2.75 and then to check it multiply it by 4 to get 11 and then divide 11 by 5 to get 2.2