It’s either very intelligent people who know most things or people that are just very good at quizzes, such as The Chase type people
Yes. If you watch Eggheads it's illuminating to hear how they reason their way to answers they don't actually know. They have a technique whereby they apply any knowledge they have about the subject, however shadowy, to work out the most likely answer. Of course, that only works well on non time-limited quizzes and there's no doubt you need excellent general knowledge of both high-brow and low-brow culture to be a dead cert in most quizzes.
If Major Ingram had had any sense he would at least have pretended to be applying some reasoning to the questions, even if he was inventing it.