Answer:
7 ÷ (a - 6)
Step-by-step explanation:
Y=kx is the direct variation equation
First plug in the x, y values given to find K
18=k(5)
18/5=k
3.6 = k
Use the k and write a new equation.
y=3.6x
Plug in the x value to solve for y.
y = 3.6(11)
y= 39.6
Answer:

And the explanation of this number is:"The number of text messages for Kendra it's 2.26 deviations above the mean"
Step-by-step explanation:
1) 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".
2) Calculate the z score
Let X the random variable that represent the number of text messages per month, and for this case we know the distribution for X is given by:
Where
and
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 the explanation of this number is:"The number of text messages for Kendra it's 2.26 deviations above the mean"
The answer is 20 because you dive it