> I don't think there's wide room for questions like that.

You'd be surprised. There is ample research showing that even the most simple math and reading comprehension questions have cultural biases.

Ok, I agree that it is possible that question like that exists (e.g counting cards)

but on the other hand they appear on previous years questions as often as other (I think), thus you can easily prepare and learn how to count cards or stuff

That's actually a perfect example. Any problem that involves cards assumes you know what cards are, what the suits are, how many of each there are, etc. That's cultural knowledge not everyone has, and often breaks down by race.

So yes, you could learn it, but the kids who grew up playing cards with their family have a distinct advantage on that question.

but still, how many questions are like that?

on math exams in my country (basic+advanced) I noticed only 1 question like that - those cards

System is not perfect, but do you have any better alternative?