Answer:
x = 6
Step-by-step explanation:

We can multiply both sides by 1.5 to isolate x

Answer:
1/3
Step-by-step explanation:
6+-5 2/3 = 6-5 2/3, so the difference is 1/3
Answer:
A sample size of at least 1,353,733 is required.
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 zscore that has a pvalue of .
The margin of error is:

98% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
You would like to be 98% confident that you esimate is within 0.1% of the true population proportion. How large of a sample size is required?
We need a sample size of at least n.
n is found when M = 0.001.
Since we don't have an estimate for the proportion, we use the worst case scenario, that is 
So






Rounding up
A sample size of at least 1,353,733 is required.
Answer:
And we can find this probability using the complement rule:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:
Where
and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the complement rule:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
Answer:
9 times
Step-by-step explanation:
Area = length x breadth
area of picture not enlarged = 3 x 5 = 15in²
If length is tripled it becomes , 3 x 3 = 9in
If width is tripled, it becomes , 5 x 3 = 15in
Area of enlarged picture = 9in x 15in = 135in²
amount by which enlarged image is larger = 135in² /15in² = 9