Question

if the mean of 5 observations x , x+ 2 , X + 4 , x + 6 , X + 8 is 11 find the mean of first 3 observations

Answer 1

5x+20=11×5
5x=55-20
x=7
there for 1st 3 obs r 7,9,11
mean=7+9+11÷3
=27÷3
=9
this is answer plz follow n mark as brialianist

Answer 2

Heya!

Here is your solution -

Mean of 5 observations = 11
Total sum = 11 × 5 = 55
5 observations = x, x + 2, x + 4, x + 6, x + 8

So, x + x + 2 + x + 4 + x + 6 + x + 8 = 55

=> 5x + 20 = 55
=> 5x = 55 - 20
=> 5x = 35
=> x = 35/5
=> x = 7

Now the first three observations = 7 (x) , 9 (x+2), 11 (x + 4)

Their mean
= 7 + 9 + 11/ 3
= 27/3
= 9

Hope it helps!! :)