help needed for q50

Ill be straight here with you.
You do mention that your quant score decreased on your 3rd attempt but do not mention what could be the reason. Get ESR from mba.co and see how did you do wrt timing and section wise.

Q48 to Q44 shows

1) You were pushed for timing.
2) You made mistakes on earlier questions and possibly on easier questions.
3) I think you have cleared CFA L1 and thus quant should be straightforward if not easy for you.
4) You dont need anything more than OGs, GMATCLUB quant tests and Magoosh (medium-hard questions only).

Go back to ESR and see what sections did you spend more than necessary time on and where did you score the lowest of the sectional scores. Then revise the theory for those sections and redo questions from GC by going to the tags viewforumtags.php. After this, you can go for GMATCLUB tests that provide you methods to do sectional quizzes and see for yourself how you are doing in those sections. Keep repeating these steps until you get a Q50-51 consistently on GMATCLUB quant tests and GMATPREP mocks. How were you doing on GMATPREP mocks and question pack 1? I will give you my example, I was consistently scoring Q51 on GC tests and GMATPREP mocks (all 4 of them, lowest was Q50). I lost concentration around Q23 on my GMAT and do remember 1-2 questions that went wrong for me (immediately realized as I clicked on next). After that I slowed down and used 70 minutes for the quant section. If I had not slowed down, I would have finished the section in 60 minutes (not recommended). Go back to the questions that you have done before, see if you could find a better/more efficient method of doing those very questions and keep a close tab of questions/subsections on which

1) You spend >2 minutes.
2) You get most incorrect answers.
3) You get correct but as flukes/lucky guesses.

Q50-51 or even Q49 is an implied score wherein the test taker has learnt all the concepts and can apply 80-85%+ concepts even on the hard questions.

It is not difficult to go for Q49-50 but it needs a bit better execution of strategies that you would already know.

Hope this helps. Feel free to PM me if you have any questions or concerns.

Good luck.