An investor sells short a December Dow (DJIA) future contract at the price of 27,870.0. At the end of the day and the following three days, the contract settles at 27,890.0; 27,810.5; 28,080.5; 27,810.0; The contract multiple is $10, the initial margin is $10,000 and the maintenance margin is $8,000. Calculate the inventors margin account at the end of the each of the four days and the profit of the trade.