Just break the questions into thirds for a rough idea.

You can select using GMATPrep questions that are "easy" "medium" or "hard" but there is no correlation between item number and difficulty level. I hope that helps.

Rebecca,
Let me restate this question, would you be able to tell the range for these level (as in OG and GMAT Prep Ques Bank) -
Hard: Range 700-800, Medium: Range 600-700, Easy: Range 500-600.

Thanks!!

Hello, Yourshail123. I thought I replied to this already, but I don't see my answer, so I will answer you again:

The difficulty level of a single question in GMATPrep® is derived from item statistics which are collected when the question was tested. We use these statistics to determine whether a question is easy, medium or hard. Your GMAT® exam score, however, is derived from your performance on all the questions in the GMAT® exam. As a single question won't directly correlate to a final score, we use the easy, medium, and hard categorisations so that you have an idea of your general performance. So, I cannot provide the exact answer you are looking for-a definitive correlation-but I hope this helps to answer your question. Thank you for asking!

I hope this helps,
Rebecca