The correct answer is 9.481.
Hope this helps.
Brainliest would be appreciated.
Answer:
He must survey 123 adults.
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
.
The margin of error is:

Assume that a recent survey suggests that about 87% of adults have heard of the brand.
This means that 
90% confidence level
So
, z is the value of Z that has a p-value of
, so
.
How many adults must he survey in order to be 90% confident that his estimate is within five percentage points of the true population percentage?
This is n for which M = 0.05. So






Rounding up:
He must survey 123 adults.
Answer:

Step-by-step explanation:
The sequence above is a geometric sequence.
The common ratio (r) = 
The common ratio < 1, therefore, the formula for the sum of nth terms of the sequence would be: 
a1 = 3
r = -2
n = 6
Plug in the values into the formula



