# The mean of the five observations x, x + 2, x + 4, x + 6, x + 8 is 11.

Answered

The mean of the five observations x, x + 2, x + 4, x + 6, x + 8 is 11. Then the mean of the first three observations is

(a) 12

(b) 2

(c) 20

(d) 9

Best answer

**Answer: (d) 9 **

**Solution:-**

The mean of five observation x, x + 2, x + 4, x + 6, x + 8 is 11.

Then, (x + x + 2 + x + 4 + x + 6 + x + 8)/5 = 11

(5 x + 20) = 11 x 5

5 x = 55 – 20

5 x = 35

x = 35/5

x = 7

Then, the value of first three observations x = 7, x + 2 = 7 + 2 = 9, x + 4 = 7 + 4= 11

So, mean of first three observations = (7 + 9 + 11)/3

= 27/3

= 9

Hence, the correct answer is option (d) 9.