We need to find out how many adults must the brand manager survey in order to be 90% confident that his estimate is within five percentage points of the true population percentage.
From the given data we know that our confidence level is 90%. From Standard Normal Table we know that the critical level at 90% confidence level is 1.645. In other words, 
.
We also know that E=5% or E=0.05
Also, since, 
is not given, we will assume that =0.5. This is because, the formula that we use will have 
in the expression and that will be maximum only when =0.5. (For any other value of , we will get a value less than 0.25. For example if, is 0.4, then 
and thus, 
.).
We will now use the formula
We will now substitute all the data that we have and we will get
which can approximated to n=271.
So, the brand manager needs a sample size of 271
Answer:
I think it's letter B, sorry I'm not sure
Answer:
4 cm.
Step-by-step explanation:
Given:
A box has a volume of 308 cm cubed.
Its height is 4 cm greater than its length.
Its length is 3 cm greater than its width.
Question asked:
What is the width of the box?
<u>Solution</u>:
Let width = 
Length = 
Height = 
<u>As we know:</u>
<u />
As width can never be in negative, 
By substituting the value:-
Width = = 4 cm
Thus, width of the box is 4 cm.
The answer is 17/36. (Fraction)
