The Official Guide set contains a total of over 1400 questions in a set of three books: GMAT Quantitative Review, GMAT Verbal Review and Official Guide for GMAT Review.
All questions in the Official Guide for GMAT® Review 13th Edition, Official Guide for GMAT® Verbal Review 2nd Edition, and Official Guide for GMAT® Quantitative Review 2nd Edition, are actual retired GMAT® exam questions. There is no overlap between questions found among the main guide, the Verbal guide, and the Quant guide.
The new guides also categorize each section by topic or type. For example, in Problem Solving, the topics include geometry area, properties of numbers, etc. In Sentence Corrections, each problem is identified with one or more grammatical issues. In Critical Reasoning, the three main categories are: argument construction, argument evaluation, and evaluation of a plan. In Reading Comprehension, there are six types of questions: main ideas, supporting ideas, inference, application of information, logical structure and tone/style.
Therefore, we highly recommend you study for the GMAT using all 3 Official Guides of the latest edition.
On March 27, 2012 the 13th Edition of the Official Guide for GMAT® Review was released. It contains 907 practice problems for the main part of the GMAT (Quant & Verbal). Of those 907 problems, 158 (about 17%) are new. This book also gives you access to 50 Integrated Reasoning practice problems on a separate website. It also contains a 100-question diagnostic test.
What remains unchanged from the 12th Edition:
On March 23, 2009 the 12th Edition of the Official Guide for GMAT® Review was released. Compared to the 11th edition, the 12th edition contains the same total number of questions. There is an overlap of approximately 2/3 of the questions found between the 11th edition and the 12th edition. The new edition contains 300 new questions not included in the 11th edition. Explanations for the overlapping questions have mostly remained unchanged. There is a slight increase in the number of Data Sufficiency problems and a slight decrease in the number of Problem Solving problems. The Diagnostic Exam, Math Review, Test-Taking Strategies and Directions are all unchanged from the 11th Edition.
Compared to the 10 edition, the 11th edition contains a similar total number of questions. Though there is an overlap of questions found between the 10th edition and the 11th edition, the new edition contains the more recently retired questions not included in the 10th edition. For those questions that do overlap, they are accompanied by modified and more understandable answer explanations.
The main benefits for you to study with Official Guides are:
Answering questions that have appeared on the GMAT exam before will give you experience with the types of questions that appear on the test. This Guide will help you learn what you need to know to answer the questions correctly.
The Official Guide for GMAT Verbal Review is an intensive study guide with 300 real GMAT questions and thorough explanations to focus your preparation on the key verbal areas of the GMAT exam. It focuses on your ability to read and comprehend written material, to reason and evaluate arguments, and to correct written material.
The Official Guide for GMAT Quantitative Review is an intensive study guide with 300 real GMAT questions and thorough explanation to focus your preparation on the key quantitative areas of the GMAT exam. It will help you solve equations, interpret data, coordinate geometry, and determine probability with assurance and ease.
In Problem Solving, all solutions provide step-by-step explanations. In Data Sufficiency, all solutions cover the reasons why each individual statement is either sufficient or insufficient. Specifically for Critical Reasoning, the solutions include a recap of the question and logics behind the question.