Suppose there is a simple index of two stocks - stock A and stock B. Stock A
opens on Monday with 7500 shares at $4.75 per share. Stock B opens on
Monday with 2500 shares at $8.95 per share. Stock A opens on Tuesday at
$4.50 per share, and stock B opens on Tuesday at $8.15 per share. Both
stocks have the same number of shares that they opened with on Monday.
What is the rate of change of this simple index over 1 day?

A. -6.7%
6.6%

C. -7.5%
D. 7.5%