A factory uses 16 tons of raw material each week (assume it works 50 weeks a year, 1 shift, 5 days a week). Each time it buys the raw material from its supplier, it pays a set up cost of $45, and its annual holding cost is $3.25 per ton. Its current purchasing policy calls for buying in batches of 20 tons. Calculate: The cost of its current inventory purchasing and management policy.