[petters]

As a TA, I've seen adults try to pass initial college calculus many times (and failing - you were allowed to try several times) with enormous effort. It's not a small multiplier

And this was still people selected from the small subset of the population choosing an engineering major. Human are much, much more different than you seem to think

[jama211]

Good for you. Those people likely didn’t have a true enthusiasm to learn the content, they just stressed and tried to cram themselves by. Kinda proves my point really.