The following data relates to an item of raw material: Cost of raw material $10 per unit Usage of per day 100 units Minimum lead time 20 days Maximum lead time 30 days Cost of ordering material $400 per order Carrying costs 10% p.a. N.B. Assume that each year consists of 48 working weeks of 5 days per week. You are required to calculate: (a) the re-order level; (b) the re-order quantity; (c) the maximum level; (d) the minimum level