Many of these are "think outside the box" type problems. For example, the one about the lightbulbs makes you think that the only information you get is binary - on or off. There are 4 possibilities - 0,1,2,3 on (position doesn't matter) but 6 configurations (123,132,213,231,312,321) making the problem impossible. The actual solution is to turn 1 on, turn a second on but turn it off just before you open the box, and leave a third off. Then it's a simple matter of checking which one's on, which one's hot and which one's off.