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3 years ago

The mean of five numbers is 8. when another number is added the mean is 7. find the number added

Mathematics

1 answer:

sasho [114]3 years ago

4 0

Answer:

$\large \boxed{\sf \ \ 2 \ \ }$

Step-by-step explanation:

Hello,

The mean of five numbers is 8 so we can write

$\dfrac{x_1+x_2+x_3+x_4+x_5}{5}=8$

When another number is added the mean is 7, let s note x the another number we can write

$\dfrac{x_1+x_2+x_3+x_4+x_5+x}{6}=7$

From the first equation we can say

$x_1+x_2+x_3+x_4+x_5=8*5=40$

So the second equation becomes

$\dfrac{x_1+x_2+x_3+x_4+x_5+x}{6}=7\\\\ \dfrac{40+x}{6}=7\\\\40 + x = 6*7=42\\\\ x = 42-40 = 2\\$

The solution is then 2

Hope this helps

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Read 2 more answers

Which graph represents an equation in the form =? Please help me!!

Genrish500 [490]

That's a question about graphs.

In the Cartesian coordinate system, we have two axes: The x-axis (horizontal) and the y-axis (vertical).

When we want to represent a equation in the cartesian coodinate system, we associate a point in the x-axis and other in the y-axis. The Cartesian coordinate is represented by (x, y).

To represent some equation in a graph, we need at least two points to draw a line that cross these 2 points.

For example: To represent the equation $y = x +1$ , let's replace the value of x:

When x = 0 → $y = 0 + 1 = 1$ . Therefore, the coordenate is (0, 1).

When x = 1 → $y = 1 + 1 = 2$ . Therefore, the coordenate is (1, 2).

Finally, if we draw a line tha cross these 2 points, we will have the graph that represents $y = x +1$ .

Now you know about it, let's solve our problem?

In that question, we should to find the graph that represents the equation $y = kx$ , but we don't know the value of k, so what should we do? It's easy:

k is a constant. That means that the value of k never changes. Now, let's analyze a specific case:

If x = 0, so y = 0 as well. But why? We know that any number multiplied by 0 is equal 0. Therefore:

When If x = 0 → $y = 0 \times k = 0$ . So, this graph cross the coordinate (0,0).

With the informations that the problem give to us, these are the unique things that we can find, but that's enough.

When we look at the options, just the second graph have a line that cross the coordenate (0, 0). Therefore, the correct answer is the graph below:

I hope I've helped. :D

Enjoy your studies! \o/

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yanalaym [24]

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2 years ago

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Answer:

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=> This is the line which has equation: x = -7.

This is a vertical line (parallel with y axis) and the slope is undefined.

Hope this helps!

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