Question

mean of five observations x,x+2,x+4,x+6,x+8 is 11 find the mean of first three observation

Answer 1

Here is the answer

First
Let's find the value of 'x'

We know that,

$\tt{Mean = \frac{sum \: of \: all \: observations}{total \: observations}}$

$\tt{11 = \frac{(x) +( x + 2) + (x + 6) + (x + 8)}{5} }$

$55 = 5x + 20$
$\tt{55 - 20 = 5x} \\ \tt{ 35 = 5x} \\ \tt{7 = x}$

Now ,
As we have got the value of x

Put value of x in the first three observations

$\tt{x = 7} \\ \tt{x + 2 = 7 + 2 = 9} \\ \tt{x + 4 = 7 + 4 = 11}$
Now,

Mean of these 3 observations

$\tt{ = \frac{7 + 9 + 11}{3} }$

$\tt {= \frac{27}{3} = 9}$

Thus ,
The mean of the first three observations is 9.

Thanks!

#BeBrainly

Answer 2

$\boxed{\boxed{\mathsf{\huge{Hello!!!}}}}$

Question
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If the mean of five observations x, x+2, x+4, x+6, x+8 is 11, find the mean of first three observation.

=>Given,

Mean of 5 Observations-x,x+2,x+4,x+6,x+8= 11

To Find Out=Mean of First 3 Observations

Solution
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$= > \frac{ x + x+2 + x+4 + x+6 + x+8}{5} = 11$

$= > \frac{5x+20 }{5} = 11$

$= > 5x + 20 = 11 \times 5$

$= > 5x + 20 = 55$

$= > 5x = 55 - 20$

$= > 5x = 35$

$= > x = \frac{35}{5}$

$= > x = 7$

The First 3 Observations are•••••••

1] X = 7

2] X + 2 = 7 + 2 = 9

3] X + 4 = 7 + 4 = 11

Hence, The first 3 Observations are 7, 9 & 11.

Now,

The mean of the first 3 Observations:---

$= > \frac{7 + 9 + 11}{3}$

$= > \frac{27}{3}$

$= > 9$
Therefore, The mean of the first three Observations is 9.

$\huge{\texttt{\underline{\underline{\underline{\underlune{Hope It Helps!}}}}}}$