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"
7- 5n=6+6(n+2)
7- 5n=6+6n+12
7 -5n=18+6n
5n-6n=18-7
-11n=11
n=-1
Answer:
3.2 x 10^13
Step-by-step explanation:
(8x10^4)(4x10^8)
reorder the terms using the commutative property
(8x4)x(10^4x10^8)
multiply
32x (10^4 x 10^8)
= 32 x 10^4+8
= 32 x 10^12
now convert to scientific notation
=3.2 x 10^13
Answer:
Tax=$0.91
Step-by-step explanation:
Tax=$12.99(.07)=$0.9093
Tax=$0.91
4x+10y=-13...you have to add the variables that are the same and then subtract the 13 from 0