We have found that the best way to negate any questions that you are afraid the admissions committees may ask you about your college background is to ANSWER THEM BEFORE THEY ARE ASKED! By this, we mean that if you are coming from a non-quantitative background, or you have not done well in your quant courses, take a course either on-line ( UC Extension) or at a local community college/university. You do not need to go to the most well known school in the area, but you do need to take accounting, finance or statistics, and look for either a B+ or an A at the time of application. You may want to check in with your top three schools to see what they recommend.
Why should you bother? Well, schools really want to know that you will be able to address the rigor of their curriculum; and if this means that you were a history major with nothing quant oriented on your transcript, or perhaps you were an econ major with a horrible semester, now is your chance to make it up!
We recommend this course of action even if your GMAT quant is above 80%; it shows you commitment to do " whatever it takes" to get ready to join the MBA program.
By the way, there is no time like RIGHT NOW to start with these courses. If you time it right, you can have a grade ready at the time of application, and another course underway before decisions go out in December. You would be able to ask your professor for mid-term grades to pass onto the adcom.
Why am I giving this advice? I was an adcom for 10 years at Wharton, and I have pretty much seen the range of stories on the quantitative side of things; trust me, you DO NOT WANT THERE TO BE ANY QUESTION THAT YOU CAN HANDLE THE RIGOR!
Other questions? Concerns about your profile? Happy to hear from you!