经典题:
Suppose that on a particular day there are 3,000 trades in a futures contract. Of the buyers in those 3,000 trades, 1,800 were closing out positions and 1,200 were taking new positions. Of the sellers in those 3,000 trades, 1,400 were closing out positions and 1,600 were taking new positions. What is the change in open interest during the day? Does it increase or decrease?
书上的答案没有看懂,想问下这题应该怎么理解,到底怎么计算open interest?
此外,如果这道题求目前的open interest,应该怎么做?