I have OG-11 , OG-Verbal and OG-Quant books and a copy of OG-10 edition. OG-11 has all ( up to 95 % , I cannot comment on RC) new questions and other 2 books (OG-Verbal and OG-Quant ) contains questions repeated from OG-10 EDITION. So, if you have OG-10 the edition,I advise you to buy only OG-11 edi...