You will find that you get more replys and sooner if you do not keep switching fonts in your posts. Changing the font apparently at random makes your posts difficult to read.
CB
You have already been told to revise the central limit theorem, do that and it will give you the result immediately. See here the section titled "Classical central limit theorem" answers this question (as asked ...).
(This is of course one of those probability and statistics questions where the wording indicates a lack of comprehension of the subject by the question setter/text book author.)
CB