Question

if the mean of 5 observations x,x+2,x+4,x+6 and x+8 is 11. then ,find the mean of the first three observations .

Answer 1

here mean =11=(x+x+2+x+4+x+6+x+8)/5
so 11 = (5x+20)/5
11= x+4
x= 11-4=7
x=7
so mean of first three observation is -
(3x+6)/3= x+2 =9
I hope you got your answer