Answer:
The company should take a sample of 148 boxes.
Step-by-step explanation:
Hello!
The cable TV company whats to know what sample size to take to estimate the proportion/percentage of cable boxes in use during an evening hour.
They estimated a "pilot" proportion of p'=0.20
And using a 90% confidence level the CI should have a margin of error of 2% (0.02).
The CI for the population proportion is made using an approximation of the standard normal distribution, and its structure is "point estimation" ± "margin of error"
[p' ±
]
Where
p' is the sample proportion/point estimator of the population proportion
is the margin of error (d) of the confidence interval.

So






n= 147.28 ≅ 148 boxes.
I hope it helps!
The greatest common factor of 10 and 20 is 10.
Answer:
Research also confirms that incisions carried out with obsidian produce narrower scars and fewer inflammatory cells. This is because on cellular level, obsidian knife cuts between cells rather than tearing it in case of a steel knife, hence, a sharper cut allows the wound to heal more easily with negligible scarring.
For this case we have the following system of equations:

When solving the problem graphically we must take into account the following:
1) The solution of the system of equations is given by the intersection of both functions.
2) The solution is an ordered pair of the form (x, y)
For this case we observe that the solution is given by:

Note: see attached image.
Answer:
The approximate solution to the system is (1.23, 4.39)
-5.25 to the nearest tenth is -5.3.