Context is everything. I got the bat-and-ball question wrong the first time I heard it because it was tossed out in passing in a presentation, but answered it just now from memory.

The other two questions were easy for me: the idea that they were 'trick questions' clearly spelled out, a reminder not to go with our first instinctive answer, and no timer.

If they were slipped into a standard maths test, or fired out during a stressful verbal interview, they might not be easy at all.