4(2x-4) = 16
4*2x - 4*4 = 16
8x - 16 = 16
8x = 16 + 16
8x = 32 / : 8
x = 4
x = total amount of students in 8th Grade.
we know only one-thrid of the class went, so (1/3)x or x/3 went.
we also know 5 coaches went too, and that the total amount of that is 41.

now, to verify, well, what do you get for (108/3) + 5?
Answer:
Step-by-step explanation:
11x+6 = 15x-26
Answer:

We can find the second moment given by:

And we can calculate the variance with this formula:
![Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246](https://tex.z-dn.net/?f=%20Var%28X%29%20%3DE%28X%5E2%29%20-%5BE%28X%29%5D%5E2%20%3D%207.496%20-%282.5%29%5E2%20%3D%201.246)
And the deviation is:

Step-by-step explanation:
For this case we have the following probability distribution given:
X 0 1 2 3 4 5
P(X) 0.031 0.156 0.313 0.313 0.156 0.031
The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.
The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).
We can verify that:

And 
So then we have a probability distribution
We can calculate the expected value with the following formula:

We can find the second moment given by:

And we can calculate the variance with this formula:
![Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246](https://tex.z-dn.net/?f=%20Var%28X%29%20%3DE%28X%5E2%29%20-%5BE%28X%29%5D%5E2%20%3D%207.496%20-%282.5%29%5E2%20%3D%201.246)
And the deviation is:
