Question

if the mean of 5 observation is x, x + 2, X + 4 x + 6 X + 8 is 13 find the value of x and hence find the mean of the last three observation

Answer 1

x+x+2+x+4+x+6+x+8/5=13
5x+20=65
5x=45
x=9
mean of last three observations
=x+4+x+6+x+8/3
=3x + 18
=3×9+18
=27+18
=45