Can I have a detailed answer please? The answer require expression and calculations.

3. (50 points) A continuous review ( Q,R) policy is implemented in an inventory system where the unit purchasing cost is $5, the inventory holding cost per unit per year is $1, the fixed ordering cost is $100, and the expected annual demand is 10000 units. The lead time demand is normally distributed with a mean of 400 and a standard deviation of 30 . All shortages are backordered at a cost of $4 per unit. (c) (15 points) Find the optimal values of the lot size and the reorder point. Perform at most three iterations (including iteration 0). Calculate the optimal expected annual cost