Can anyone get this??

The men all put up their hands so there must be 2 black, 1 white or 3 black. If it's 3 black none of them can tell, it's just a guess. If it's 2 black 1 white then each of the blacks would see 1 black 1 white and would know that they must have the other black. Whichever of those two is smarter will get the job.

That guy has a white mark.
Everybody raised their hands meaning that the other two saw one black and one white mark. Since both marks he sees are black, he knows his is white.

Well....if there are 2 black and 1 white, then it makes sense that the guy who has the white mark would see that the other two guys have black marks and, by deduction, realize he has the white mark. Wouldn't he? But then too... it also stands to reason that if each of the other two has a black mark and see a white and black mark, they would know they have a black mark. You think they would figure that out sooner than "after a few minutes" though. So I guess I don't know the answer!

Or...do they know that there are 2 blacks and one white? If not, then the one with the white mark would know he has the white mark because the other two have black marks.

Piffka got it, oddly enough I was once asked this question at a job interview back in the sixties.

I disagree.
There is nothing to say that they don't all have black marks.
The fact that they all raise their hands means that they all see AT LEAST 1 black mark. Just because one of them sees 2 black marks doesn't mean that he has a white mark, he may have another black mark.
The only way any of them can be SURE is if there are 2 blacks and 1 white.
In that case the 2 guys with black marks each see 1 black and 1 white on the other 2. That means they MUST have a black mark themselves because otherwise they wouldn't all have their hands up. If they had a white mark then the man they can see with the black mark would be looking at 2 whites and therfore wouldn't have his hand up.
Make sense?
Bit of a rort really, the guy with the white mark has no chance.

Yes Adrian it makes sense to me because I already know the answer but this one always was a bitch to try and explain to someone else.

The three men are intelligent, yet nobody got the answer immediately. As Adrian pointed out, if only two had black, those two would know immediately that they had black. Therefore, they all have black. The third guy was smarter because he recognized that his must be black or either of the other two would have answered immediately.