[defcon1_es]

Ampliando la solución que te ha dado ecfisa:

Código Delphi [-]
procedure TForm1.Button1Click(Sender: TObject);
var
  i, r, c: Integer;
begin
  r := 0;
  c¨:= 0;
  for i := 0 to ComponentCount-1 do
  begin
   if Components[i] is TComboBox 
   then begin
      r := r + StrToInt(TComboBox(Components[i]).Text);
      c := c + 1;
   end;
  end; 
  nfinal.Text := FormatFloat('#,##0.##', r/c);
end;