Practice problem for Ch 2 At the end of last business day the open interest was 2000 contracts. During the day Alex (who started the day with a long position in 400 contracts) sold 300 contracts to Bob (who started the day with a short position in 500 contracts), sold another 170 contracts to Charles (who did not have any position at the beginning of the day), and sold another 135 contracts to David (who started the day with a short position in 50 contracts). No other trades were made during the day. Question: what is the open interest at the end of the day