Bud opened a flower shop. he rented a building for $9,000 a year. to buy equipment for the store, he withdrew $10,000 from his savings account, which earned an annual interest rate of 3 percent. during the first year of operation, bud paid $4,000 for utilities and $12,000 to his suppliers. the store's total annual revenue was $55,000. the market value of the store's equipment at the end of the year was $8,000. if bud had not started this business, he would have continued to work as an employee at another flower shop for $30,000 a year. what was bud's opportunity cost of running his business?