1:5-4 Sergio owns 200 shares of Palm Corporation common stock, purchased during the prior year: 100 shares on July 5, for $9,000; and 100 shares on October 15, for $12,000. When Sergio sells 50 shares for $8,000 on July 18 of the current year, he does not identify the particular shares sold. Determine the amount and character of the gain.