My friend and I were playing chess the other day, and while he was admiring some birds in the park I pulled a fast one and stuck one of my pieces back on the board. Unfortunately, my new-found criminal career was doomed from the start, for he quickly noticed my deception. “Did you see me [...]
Today’s post is going to be a riddle; I figured it was about time for another one. You and I both have envelopes filled with money. My envelope contains either double or half the amount of money that’s in yours. If you want, I’m going to let you switch envelopes. Should you stay, switch, or [...]
I will give you $1 million to answer a yes or no question either truthfully or falsely. Would you take me up on this offer? Please use rot13 to encode your answers so as not to ruin the puzzle for anybody else.
I’m posting all these puzzles because Yat said he thought that logic puzzles are becoming stale, and I’m trying to prove him otherwise. There are two types of inhabitants in the world: humans and vampires. Humans always tell the truth and vampires always lie. Also, inhabitants can either be sane or insane. Someone who is [...]
Since my other Raymond Smullyan puzzle was so popular, I’m adding another one. As always, you can find his riddles in his books in much greater depth. A perfect logician goes to visit the island of knights and knaves. Knights always tell the truth and knaves always lie. There is no one else on the [...]
It’s from Raymond Smullyan’s book The Lady or the Tiger and in my opinion it is the best logic puzzle ever written. You want to buy a truth machine. They are machines that have two lights, red and green, and truthfully answer any yes or no question. The truth machine store has three machines in [...]