Hi vaheb,
Since you're going to see just 4 RC passages on Test Day - and the difficulty level of those prompts will adapt to how you are performing on the overall Verbal section - then the practice RC materials that you'll see in the
OG may be easier/in-line-with/harder than the prompts that you face on the Official GMAT. It's also worth noting that working on RC out of a book - and focusing on JUST RC for several prompts in a row (that might all be the same general difficulty level) - will likely impact your overall performance. In simple terms, it might 'feel' easier because how you are practicing isn't a great 'match' for how you will face RC on the Official GMAT.
Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied? How many hours do you typically study each week?
2) What study materials have you used so far? What “brands” of CATs/mocks have you used?
3) On what dates (or approximate dates) did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) What is your overall goal score?
5) When are you planning to apply to Business School and what Schools are you planning to apply to?
760+: What GMAT Assassins Do To Score at the Highest LevelsGMAT assassins aren't born, they're made,
Rich