5x^2 - 80 = 0
5x^2 = 80
x^2 = 80/5
x^2 = 16
x = sqrt 16
x = (4,-4) <===
She will get 23 books.
So, first, you take the shipping away to get $93.05,
then you divide $93.05 by $3.95 which equals 23.55
and you can't have half a book; so it's 23!
A Z-score helps us to understand how far is the data from the mean. The correct option is B.
<h3>What is Z-score?</h3>
A Z-score helps us to understand how far is the data from the mean. It is a measure of how many times the data is above or below the mean. It is given by the formula,

Where Z is the Z-score,
X is the data point,
μ is the mean and σ is the standard variable.
The weight of a randomly selected pack of gum has a z-score of 3.11. Therefore, The weight of this pack of gum is heavier than the mean weight by 3.11 standard deviations.
Hence, the correct option is B.
Learn more about Z-score:
brainly.com/question/13299273
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