Question

If the mean of five observations x, x + 2, x + 4, x + 6 and x + 8 is
11 then the value of x is

(A) 5

(B) 6

(C) 7

(D) 8

Answer 1

Correct option is (C) 7

Given observations are x, x + 2, x + 4, x + 6 and x + 8

\(\therefore \text { Mean }=\frac{\text {Sum of observations}}{\text {number of observation}}\)

\( \Rightarrow \frac{x+x+2+x+4+x+6+x+8}{5}=11 \)

\(\Rightarrow \frac{5 x+20}{5}=11 \)

\(5 x+20=55\)

\(5 x=55-20 \)

\(5 x=35 \)

\( \therefore x=\frac{35}{5}=7\)

Answer 2

AnkushLather, hello

Adding the five observations and dividing by 5 to arrive at 11 gives us:

(5x+20)/5 = 11

Then the value of x is (C) 7