If daily demand is normally distributed with a mean of 15 and standard deviation of 5, and lead time is constant at 7 days, a 95% service level will require how much safety stock?

Jiffy printing shops does a lot of printing job for college students. the shop use an average of 25 cases of copy paper each day during the 312 days last year. the shop opens 6 days a week for 52 weeks each year and closes on sundays. each case of paper costs $35. it conducts a count of its paper inventory at the end of every quarter of the year. the table below shows the inventory counting records for last year. inventory end of quarter 1 700 cases end of quarter 2 1,050 cases end of quarter 3 920 cases end of quarter 4 800 cases 1. what's jiffy's cost of goods sold last year? 2. what's jiffy's average aggregate inventory value? 3. what's jiffy's inventory turnover last year? 4. what is the printing shop's weeks of supply last year?