Answer:
Standard deviation of the students = 0.408
The students would you have to poll to be 95% confident of the outcome within /- 2% of the vote
= 0.408 X 1600
= 652.8
Step-by-step explanation:
<u><em>Step(i):</em></u>-
Given sample size 'n' = 1600
95% confidence interval of the margin error is determined by

Level of significance = 0.05
Z₀.₀₅ = 1.96
Given Margin of error = 2% = 0.02


0.02 X √1600 = 1.96 X S.D

Standard deviation of the students = 0.408
The students would you have to poll to be 95% confident of the outcome within /- 2% of the vote
= 0.408 X 1600
= 652.8
Factor out the common terms in the first two terms, then in the last two terms;
3x^2(b - 3x) - (b - 3x)
Factor out the common term b - 3x
<u>= (b - 3x)(3x^2 - 1)</u>
Step-by-step explanation:
It's a proportion.
Here is your process:
15*4=60
60/20=3
3=y
:)
Subtract original amount from new amount:
84 - 39 = 45
He bought 45 books.