Here everybody can post a puzzle/enigma and the rest of the JCC can try to answer. Just few rules -There are no constraints on the kind of enigma that someone can propose, but whoever asks is supposed to know the solution and possibly to add a warning if it requires extra-ordinary knowledge on some topic. -Questions should be numbered and with a title in bold. -Answers always under spoiler tag. The answer must contain the number of the question outside the spoiler tag. -You can post as many questions as you want, no matter whether the previous ones already have a solution (and this is why numbering the questions is useful). I will start with a relatively famous one 1) Monty Hall problem Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. (Suppose you really prefer the car over a goat). You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice? So, if possible, in this case the answer should have the form 1) Spoiler **whatever the answer is ** ^ This problem usually stimulates quite heated discussions. At a family dinner we discussed for hours, and at the end I think that I failed to convince my father of the correct solution.