the average monthly demand for bathtubs was 400. the selling price of the bathtubs was R7500 and a mark-up of 50% on cost was used. all the sales are on credit and the credit terms are 60 days. collection costs of approximately R50 per unit sold were incurred. the annual holding cost of a bathtub was 1% of the cost of the item. the cost of placing an order for bathtubs was R18.75. the cost of capital was 12%. calculate the annual ordering costs based on the EO