Answer:
15m+80 would be the correct equation
If my calculations are correct the correct answer is 4
Take the difference between Tiffany's score and the average:
53 - 67 = -14
Divide this difference by the standard deviation to get the <em>z</em>-score:
(53 - 67)/5.5 = -14/5.5 ≈ -2.55
What your problem is cut off
You need to figure out how many hours does he need to read one book.
8.5 / 4 = 2.125
Hope this helps! (: