Final answer:
Sean should use the formula =A1*(A2+A3) to calculate the total weight of the items being shipped by multiplying the number of items by the sum of the weight of each item and the weight of the packaging.
Step-by-step explanation:
The formula Sean should use to calculate the total weight of the items being shipped is:
=A1*(A2+A3)
This calculation multiplies the number of items, which is in cell A1, by the sum of the weight of each item plus the weight of the packaging for each item, which are in cells A2 and A3 respectively. Since each item weighs 180 pounds and the packaging weighs 10 pounds, you add the item weight (180) to the packaging weight (10) and then multiply by the number of items (cell A1) to get the total weight.