Sara had 88 dollars to spend on 8 books. After buying them she had 16 dollars. How much did each book cost?

Suppose there is a simple index of three stocks, stock abc, stock xyz, and stock qrs. stock abc opens on day 1 with 4000 shares at $3.15 per share. stock xyz opens on day 1 with 5000 shares at $4.30 per share. stock qrs opens on day 1 with 6000 shares at $4.60 per share. the price of stock abc on day 8 begins at $3.50. the price of stock xyz on day 8 begins at $3.90. stock qrs opens on day 8 with a price of $4.50 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?

Ineed someone to me answer my question i have to have this done and knocked out

Find an bif a = {3, 6, 9, 12) and b = {2, 4, 6, 8, 10).