Can you help me with all 3 parts and show me what cells to use in Excel to solve. Thank you!

Weekly demand for Dell computers at a Costco store is normally distributed, with a mean of 250 and a standard deviation of (150+ 22). The store manager continuously monitors inventory and currently orders 1,000 computers each time the inventory drops to 600 units. Dell currently takes two weeks to fill an order (lead time).

1. How much safety inventory does the store carry?

2. What CSL does Costco achieves as a result of this policy?

3. How much safety inventory should Costco carry if they desire to improve its CSL by 10%?