contrlc Begin readarrreal(6).Average.ToString.Println; end.

"Школьный вариант":

const
  N = 6;

 var
  i: integer;
  ar: array[1..N]of real;
  s: real;

 begin
  s := 0;
  for i := 1 to N do
   begin
    read(ar[i]);
    s := s + ar[i];
  end;
  write(s / 6);
end.