Do i divide 256 by 2 and get 128 or is that not how this one works !

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?

Given the statements, "a square root of 16 is 4," and "a square root of 9 is -3," complete the following blanks with the correct truth-values. p is and q is , so the statement, "a square root of 16 is 4 or a square root of 9 is -3" is .

Pls! does anybody know a shortcut for answering these types of questions in the future?