Please show work in full detail with formulas, i do not have excel and need to understand how the problem is worked by hand

Inventory Management: 3. The Italian eatery at the Student Union orders pre-made, frozen calzones from a gourmet food distributor. They cost $2.50 apiece. Ordering costs are $10 per order, and orders always take 4 days to arrive. The demand over a term (for which the eatery is open 100 days) averages 80 calzones a day, with a standard deviation of 20 calzones per day. Holding costs are 10% of the Eatery's purchase price. a) What is the economic order quantity for calzones? b) if the management has specified that the risk of a stock out during a cycle is 15.87%? What is the Reorder point? c) What is the annual holding costs and annual ordering costs if we use the EO