A market value weighted index has three stocks in it, priced at 66, 78, and 69 per share, and each firm has 466, 496 and 269 thousand shares outstanding, respectively. The value of the index today is 980. Over the course of a month, the market does its random walk-y thing, and the prices of the three stocks change do 84, 31, 90, respectively. What is the new value of the index?

Could you explain how to find the new value of the index.