if the mean of the observations x, x+3 ,x+5 ,x+7, and x+10 is 9. what is the mean of last three observations.

Question

if the mean of the observations x, x+3 ,x+5 ,x+7, and x+10 is 9
what is the mean of last three observations

Manmeet Singh · Accepted Answer

if the mean of the observations x, x+3 ,x+5 ,x+7, and x+10 is 9. what is the mean of last three observations.

The mean is calculated as:

$M e a n = \frac{s u m o f o b s e r v a t i o n s}{n u m b e r o f o b s e r v a t i o n s} \Rightarrow 9 = \frac{x + x + 3 + x + 5 + x + 7 + x + 10}{5} \Rightarrow \frac{5 x + 25}{5} = 9 \Rightarrow 5 x + 25 = 45 \Rightarrow 5 x = 20 \Rightarrow x = 4$

The last three observations are: x + 5, x + 7, x + 10

The mean = $\frac{x + 5 + x + 7 + x + 10}{3} = \frac{3 x + 22}{3} = \frac{3 \times 4 + 22}{3} = \frac{34}{3}$

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