deep water mining added $500 to retained earnings last year on sales of $20,500. the administrative expenses were $4,500, depreciation was $850, dividends paid were $350, and the interest expense was $150. what was the cost of goods sold if the total tax rate was 21 percent? a) $20,225 b) $24,385 c) $18,457 d) $14,328.500 e) $21,393