Linked Questions

3
votes
1answer
362 views

100 Cards with numbers in a room [duplicate]

The scenario is like this: There's a room, inside the room there are 100 cards with numbers [1,100] on them (No duplications), the cards are ordered randomly. Two persons stand outside the room, ...
1
vote
1answer
152 views

Don't Fail MY Exam [duplicate]

A professor decides the following grading scheme in his class. After the final exam is graded, he keeps all the papers upside down on his table in a random order so that no student can recognise his ...
57
votes
5answers
9k views

How to beat Count Dracula

Abraham Van Helsing and Jonathan Harker play a game against Count Dracula. The three players agree on the following rules: Count Dracula and Van Helsing enter the crypt, while Jonathan Harker ...
17
votes
5answers
1k views

100 Prisoners' Names in Boxes - Save them all!

This puzzle is based on 100 Prisoners' Names in Boxes: Names in Boxes The names of 100 prisoners are placed in 100 wooden boxes, one name to a box, and the boxes are lined up on a table ...
12
votes
4answers
836 views

How to rate difficulty of a classic riddle?

How, as a writer of riddles, can I rate their difficulty? I guess, for me alone, knowing the answer even before the riddle existed, it's pretty much impossible, and I should need some external help. ...
11
votes
4answers
2k views

Help me find my favourite DVD

I have an admission to make: I very rarely put my DVDs back in the case they came from. Whenever I watch a new DVD I just put whatever DVD is the player in the new case. I put the cases back on the ...
5
votes
1answer
730 views

Shuffling Cards

I was just thinking about this. Let's say that we have a card deck with 54 cards and the $n$th card from the top is flipped. We repeat a short process of cutting the deck directly in the middle and ...
10
votes
2answers
1k views

Let's deal with “Names in Boxes” Safely

I met a puzzle, which is basically well known 100 Prisoners' Names in Boxes , but... it has an algorithm, which gives prisoners 100% chance to survive! This is achieved by a small change in the ...
4
votes
2answers
261 views

100 prisoners' names in boxes, against smart warden

My question, which I do not know the answer to, concerns the classic 100 prisoners and 100 boxes puzzle, summarized below. The solution to this assumes the names are placed in boxes randomly, and gets ...
5
votes
1answer
408 views

A “Puzzling” Cipher

I thought I'd put together a simple cipher for all of you Puzzling lovers out there. If you need help, you can always look to the wisdom of the past for guidance. The answer is a single word, and each ...