While you are right to be concerned about your GMAT quant score, there are other aspects to your candidacy that show that you can handle this aspect of an MBA program. What you need to do is write an essay outlining your quant abilities and accomplishments in the optional section and state that the test results are not indicative of your analytical abilities.
Of the schools you are applying to, the only two where I think the GMAT issue might be a problem are Chicago and Yale. However, even with these two schools, if you explain your quant score properly and provide supporting information correctly, this might mitigate the quant score to a degree.
Good luck on your applications. I recommend that you stop worrying about this one aspect of your candidacy and start working on your applications as they are difficult and take much more time than most people expect.
Senior Admissions ConsultantManhattan Review
Manhattan Review GMAT Prep & MBA Admissions Consulting
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