Using the z-distribution, it is found that a sample size of 3,385 is required.
<h3>What is a confidence interval of proportions?</h3>
A confidence interval of proportions is given by:

The margin of error is:

In which:
is the sample proportion.
In this problem, we have a 98% confidence level, hence
, z is the value of Z that has a p-value of
, so the critical value is z = 2.327.
We have no prior estimate, hence
is used, which is when the largest sample size is needed. To find the sample size, we solve the margin of error expression for n when M = 0.02, hence:





n = 3,385.
A sample size of 3,385 is required.
More can be learned about the z-distribution at brainly.com/question/25890103
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B. To be careful, use brackets: 10(1*2) + 4x which will be 20 + 40x or as you have it, 10*2 + 40x.
Answer:
7 chocolate bars will cost $35
Step-by-step explanation:
if 3 cost $15 then 1 bar would cost 5 dollars and 5x7=35
here is a ratio:
<u>3</u> = <u>7</u>
15 = 35