Hello, Gagan. The OG12 does not include the new Integrated Reasoning section, so you will still need to purchase test materials for that section. The OG13 includes 50 IR questions, as well as 155 new questions in the Quant and Verbal section. As for whether the OG13 will be sufficient, that depends largely on your own individual skill level in the quant section. You may want to take a practice exam to see if your scores are within the range you are targeting. You can take the practice exam in your OG book, or download GMATPrep (https://www.mba.com/store/product-info.a ... ID=80.0027). I hope that helps!