Question

Choose the correct answer in each of the following questions:
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

ANSWER:
(c) 7
Mean of 5 observations = 11
We know:
Mean=Sum of all observations/Total number of observations ⇒11=(x+x+2+x+4+x+6+x+8)/5⇒11=5x+$\frac{20}{5}$⇒5x+20=55
⇒5x=35⇒x=7