2. Will the real GMAT also have some 15-20 qns in RC in the beginning and some 30 odd CR questions??
No, you will not see 15-20 questions on RC followed by 30 complex CR questions.
The real GMAT test will only have about 4 RC passages (or 12 RC questions).
CR you may see around 13-14 questions
SC you may see around 14-15 questions
And those questions will be randomized...except for RC questions which will come in a series (questions related to that passage will be given before moving on to another question type).
In total, there should be 41 questions. So the diagnostic section in the OG is really just a series of questions. Don't use that to gauge what's going on in the actual test.
Try a GMAT Prep practice or a GMATPill practice test
to get more of a sense of what to expect.
... and more
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