Answer:
around 153.94
Step-by-step explanation:
The formula is pi * radius squared
so pi * 7^2 is
pi * 49 = around 153.94
We'll have a rectangle. In this attached photo, you can easily observe it. Its sides are going to be 6 and 8 and it will be parallel to the sides. The area of this rectangle is A=6*8=48 cm²
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
the cost for each of jelly beans and each pound of trail mix is $2.5 and $1.75
<u>Step-by-step explanation:</u>
Given A store is having a sale on jelly beans and trail mix. For 3 pounds of jelly beans and 2 pounds of trail mix, the total cost is $11. For 5 pounds of jelly beans and 6 pounds of trail mix, the total cost is $23 . We have to find the cost for each pound of trail mix and each pound of jelly beans.
Let the cost of each pound of trail mix is $y.
and the cost of each pound of jelly beans is $x.
According to question,
For 3 pounds of jelly beans and 2 pounds of trail mix, the total cost is $11.
⇒
→ (1)
For 5 pounds of jelly beans and 6 pounds of trail mix, the total cost is $23
⇒
→ (2)
Solving (1) and (2), we get
3(1 equation)-(2 equation)=0
⇒
⇒
hence,
⇒
⇒
Putting
in
we get ;
⇒
⇒ 
⇒ 
⇒ 
Hence, the cost for each of jelly beans and each pound of trail mix is $2.5 and $1.75 .