The correct option is 20.
The score found for the sample is 20.
<h3>What is Standard error?</h3>
A standard error is a statistic that is applied to test the distribution of data. This metric is comparable to standard deviation. We can calculate the standard error if we know the sample size & standard deviation. It assesses the mean's precision.
Now, according to the question;
Sample mean; 
Sample variance; 
Thus, 
Standard error SE = 1
The amount of scores with in sample must be determined here.
The standard error formula is as follows:

We might rearrange the formula as follows:

Substituting the values;

The sample's number of scores n = 19.98 = 20 (round up)
Therefore, the scores are in the sample is 20.
To know more about the Standard error, here
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The answer is B.
(the equation to solve this with is: a^2 + b^2 = c^2)
It can help you by checking your answer
27.75/5 = $5.55 per book
32.16/6 = $5.36 per book
The online store is the cheapest because it has the lowest unit rate
I think the answer is 6 since u multiply them