Suppose there is a simple index of three stocks, stock ABC, stock XYZ, and stock QRS. Stock ABC opens on day 1 with 8000 shares at $4.25 per share. Stock XYZ opens on day 1 with 5000 shares at $2.90 per share. Stock QRS opens on day 1 with 2000 shares at $6.40 per share. The price of stock ABCon day 8 begins at $3.90. The price of stock XYZ on day 8 begins at $2.50. Stock QRS opens on day 8 with a price of $6.10 per share. Assume that each stock has the same number of shares that it opened with on day 1. What is the rate of change of this simple index over 1 week?