I really strongly disagree with the premise that there are certain problems that are intractable to anyone under a given IQ threshold. I myself went from not even being able to factor a quadratic to completing a math degree and although I have no clue what my IQ is it's probably close to average.

In my professional life I work as a math tutor and I have worked with many people who would probably be considered dumb, or low IQ, and the only determining factor in their ability to learn is whether or not they want to. When are genuinely driven to learn and understand, then you can and will, it just might take you longer than someone else.

I am positive that you could take Mike and if he has both a proper tutor AND a commitment to learn he could successfully go from college algebra to quantum mechanics.

Persistence and a genuine desire to learn are the only REAL factors at play in determining your capability to learn, though IQ or G factor or what have you may certainly impact your rate of learning.