how are these numbers being found ?

Exercise 4.3 Assume that Barnaby's Hideaway will change its ordering system from a perpetual system to a periodic system, ordering nonperishables every two weeks. Given the following amounts of each found on the shelf, determine the amounts to order for each of the items in Exercise 4.2. Add 50 percent to the amounts calculated as a safety factor Canned Tomato Juice, 10 cans Canned Peaches, 9 cans Canned Black Olives, 6 cans (explanation) 3 Canned Tomatoes 4 5 Amount required for upcoming period 6 Amount on hand 7 8 Amount need until delivery + safety factor 9 Amount to order 10 11 Canned Peaches 12 13 Amount required for upcoming period 14 Amount on hand 15 16 Amount need until delivery + safety factor 17 Amount to order 18 19 Canned Black Olives 20 21 Amount required for upcoming period 22 Amount on hand 23 24 Amount need until delivery + safety factor 25 Amount to order (explanation (explanation) 26 Canned Tomatoes Amount required for upcoming period Amount on hand 28 10 18 15 33 (explanation) Amount need until delivery + safety factor Amount to order rounded to 6 cases Canned Peaches Amount required for upcoming period Amount on hand 5 Amount need until delivery + safety factor Amount to order 3 Canned Black Olives 42 -9 33 22 55 (explanation) rounded to 5 cases 1 Amount required for upcoming period 2 Amount on hand 3 4 Amount need until delivery + safety factor 5 Amount to order 14 -6 8 8 16 (explanation) rounded to 1 case