mark gunther and sony are trying to determine the safety stock (ss) and reorder point (r) for its circuit cards. it takes 5 (business) days for sony to receive its cards, corresponding to a lead-time of 5 days. mark estimates that the daily demand for sony is 400 cards on average with a daily standard deviation of 30 units. after long conversations with the management team, samsung agrees to target a 93% service level. what is the appropriate safety stock (ss)?