What does this problem mean and how do you do it? I don't need an answer just an explanation?

Question

The problem: If the average of three numbers is V If one of the numbers is Z and is Y, what is the remaining number?
Multiple choice answers: ZY-V or z/v -3-Y or z/3-Y-Y or 3V-Z-Y this is the correct answer or V-Z-Y.

Answer 1

Let's work this out logically.

The average of three numbers, by definition, is

V = (x1 + x2 + x3)/3

Since we're given two of the numbers to be Z and Y, let's let the third number be X.

V = (X + Y + Z)/3

To find the remaining number, all we have to do is solve for X (since we have Y and Z).

Multiply both sides by 3,

3V = X + Y + Z

Now, solve for X. Move Y and Z to the left hand side.

3V - Y - Z = X

Answer 2

I will do my best......
Knowing that the average of three numbers is made up by adding those numbers up (z, y and (lets say X))and then dividing it by 3. In order to get to the final number the only way to do that is to take the average #, V and multiply it by 3, then subtract the two variables (z and y) leaving you with the 3 third number X.

An example.... Here is what you know:
The average of 3 numbers is 210.(V)
You know 2 numbers 245 (z) and 362 (Y)
so 3V-Z-Y or
210(3)-245-362= 610-245-362=123.

Answer 3

The average is the sum of the items divided by the number of items. To find the average of three numbers, you add them up and then divide by 3.

So...

average is V, two numbers are Z and Y. Let's call the missing number X.

V = (X+Y+Z)/3

We want to solve for X (the missing number), so:

3V = X+Y+Z
3V - Z - Y = X

Answer 4

The average of three numbers, by definition, is

V = (x1 + x2 + x3)/3

Since we're given two of the numbers to be Z and Y, let's let the third number be X.

V = (X + Y + Z)/3

To find the remaining number, all we have to do is solve for X (since we have Y and Z).

Multiply both sides by 3,

3V = X + Y + Z

Now, solve for X. Move Y and Z to the left hand side.

3V - Y - Z = X

Answer 5

You have 3 numbers you are adding together:

Y + Z + ?

You would divide the answer by 3 to find the average (V).

Therefore Y + Z + ?/3 = V

Multiply both sides by 3.

Then subtract Y and Z from both sides to find your missing number (?).

Your answer is definitely in your choices.

Answer 6

Let x be the 3rd number.
Then (Z+Y+x)/3 = V
(That's the definition of average.)
Now solve for x:
3V = Z+Y+x
x = 3V-Z-Y.

Answer 7

x=3V-y-z


(x+y+z)/3=v
x=3v-z-y