Answer:
Where
and 
Since the distribution for X is normal then the distribution for the sample mean is also normal and given by:



So then is appropiate use the normal distribution to find the probabilities for 
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". The letter
is used to denote the cumulative area for a b quantile on the normal standard distribution, or in other words: 
Solution to the problem
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where
and 
Since the distribution for X is normal then the distribution for the sample mean
is also normal and given by:



So then is appropiate use the normal distribution to find the probabilities for 
<span>D. Regular polygon.
</span>A polygon that has all sides the same measure and all angles the same measure is called Regular polygon.
Hoped I helped!
Answer:
the answer for -k/3=9 is K= -27
Step-by-step explanation:
hope this helps. if you want the steps let me and i will put it their
Step-by-step explanation:
Cost = $112
30% discount coupon on the item he's going to buy
=$112 × 30/100 (or you can write 30%)
=$168/5 ($33.6)
7% tax on the item=$112 × 7/100(or you can write 7%)
= $196/25 ($7.84)
Total amount altogether=$112 - $33.6 - $7.84
=$70.56
not sure for the answer^^