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If the mean of 5 observations x x + 2 x…

September 7, 2022 by Prabhat

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If the mean of 5 observations x, x + 2, x + 4, x + 6 and x + 8 is 11, then the mean of the last three observations is-

A. 11
B. 13
C. 15
D. 17

Answer: Option B

Here is complete explanation of If the mean of 5 observations x x + 2 x….

Solution(By ExamCraze Team)

We have :
$$ Rightarrow frac{{x + left( {x + 2} right) + left( {x + 4} right) + left( {x + 6} right) + left( {x + 8} right)}}{4} = 11$$
$$eqalign{ & Rightarrow 5x + 20 = 55 cr & Rightarrow x = 7 cr} $$
So, the numbers are 7, 9, 11, 13, 15
∴ Required mean
$$eqalign{ & = left( {frac{{11 + 13 + 15}}{3}} right) cr & = frac{{39}}{3} cr & = 13 cr} $$