I think both of them are, because none of the problems are really good for explaining your thought process. In fact, it is a contradiction to try and think about a solution to a problem and to give a dissertation on how you're thinking about the problem. You can do one or the other, and in the latter case you have to have solved the problem previously.

What I do is ask people about a problem they have solved and get them to teach me about it. If I learn something then it's a good result.

Asking people to solve a trivial problem AND let you into the inner workings of their brain-- normally a non-verbal activity- isn't testing their abilities.