Answer:
Karen needs to spend $4.5 to buy new hair bands.
Step-by-step explanation:
Given:
Hair bands Karen have = 3
cost of 8 hair bands = $1
Total Hair bands she require = 39
Hence Number of of new hair bands require = Total Hair bands she require - Hair bands Karen have = 39 -3 = 36
we need to find how much money she need to spend to buy new hair bands.
cost of 8 hair bands = $1
Cost of 36 hair bands = money need to spend on hair bands
By using Unitary method we get;
Money spend on new hair bands = 
Hence,Karen needs to spend $4.5 to buy new hair bands.
Attached below is the problem that I worked out. And I checked my answer simply by plugging it in
Answer: Do you need it all of it?
Step-by-step explanation:
Answer:
The 95% confidence interval for the proportion of students who get coaching on the SAT is (0.1232, 0.147).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the z-score that has a p-value of
.
427 had paid for coaching courses and the remaining 2733 had not.
This means that 
95% confidence level
So
, z is the value of Z that has a p-value of
, so
.
The lower limit of this interval is:

The upper limit of this interval is:

The 95% confidence interval for the proportion of students who get coaching on the SAT is (0.1232, 0.147).