Homework. Il Example sales on cash, A retailer has 500,000 baht of monthly sale on average. The cost of goods sold is 50% of sale, while operating cost, excluding depreciation, is 100,000 baht per month. The owner needs 50,000 baht per month for his/her living expense. The retailer holds inventory enough to sales for 2 months, and receives 1 month credit on purchase of inventory from suppliers. How much fund is needed for working capital