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Questions tagged [cards]

For puzzles centered around playing cards.

4
votes
4answers
156 views

What is the minimum High Card Points needed for a partnership to be able to claim all 13 tricks in Bridge?

Assume you have basic knowledge of how a contract bridge game plays. There are 40 total HCPs in a set of cards. 4 for each Ace, 3 for each King, 2 for each Queen and 1 for each Jack. What is the ...
10
votes
1answer
494 views

Perfect riffle shuffles

Take a deck of cards (with indexed position from 1 (top) to 52 (bottom)) and perform a perfect riffle shuffle, such that the top card (1) is still on top and the bottom (52) is still on the bottom. ...
3
votes
4answers
177 views

Randomly selecting cards using 6-sided dice

There is a pile of $5\leq N\leq15$ cards. $x=3$ or $6\leq N$ cards need to be randomly chosen from this pile (uniform distribution). To do this any number of $6$-sided dice can be rolled any number ...
6
votes
1answer
260 views

A message sent to me in spell cards

My brother went missing a few days ago. No one has seen him since then. The day he went missing, I saw the following arrays of my new Dungeons and Dragons spell cards. I didn’t think much of it then, ...
3
votes
2answers
130 views

make a sum with cards

Take the numbered diamond cards in a standard deck, that is those from 2 to 10. You may use some of them to form a sum: for example 23+45=68. What is the maximum result you may obtain? I hoped there ...
1
vote
1answer
391 views

How many Dobble symbols are there? [closed]

The game of Dobble (will edit in a link later) involves a set of bespoke playing cards covered in symbols or small pictures - a dog, an arrow, a pencil, a tree etc. Each card contains eight such ...
10
votes
7answers
444 views

A cooperative guessing game - Guess your order and card

6 players sitting in a circle and each assigned a card among 2 Hearts, 3 Hearts, ..., Ace Hearts (i.e. any of the Hearts cards). Holding her card above his forehead (i.e. Indian Poker fashion), each ...
1
vote
0answers
105 views

The magic trick [duplicate]

I am here to tell you about two brothers that were doing a magic trick. But not the kind with smoke and mirrors but just a deck of cards and the magic of the human mind. Will you be able to match the ...
0
votes
1answer
131 views

A complex problem from Garena 2017 challenge [duplicate]

The problem is quite complex and I would really like to know the solution.
6
votes
3answers
2k views

Pick one card magic

At a dinner last night, my friend Lan did a magic trick. Any ideas how it worked? First, Lan took a number of cards out of a 52-card deck. I don't know exactly the number of card. To be sure that the ...
5
votes
1answer
215 views

Who's the winner of this card game?

During a round of a card game big two, two players decide to show off their hands. The 1st player has ♥3 ♥4 ♥4 ♥6 ♥6 ♥8 ♥8 ♥K, and the 2nd player has ♠7 ♠9 ♠9. It's the 1st player's turn, and ...
4
votes
1answer
1k views

98 Cards: Optimal Strategy with Rule of Ten's

I recently found the game "98 Cards" by VdH and wondered if there is an optimal strategy to play it. Rules: There is only one player. Cards with each of the numbers $2$ to $99$ are contained in the ...
5
votes
5answers
633 views

Card trick with two assistants giving two cards each from a 53 card pack (with joker)

A long time ago, I saw on a website (with a grec sounding name i can't remember), a card trick I've passed a long time trying to solve. I hope it has never been posted there and i'm sure it will ...
3
votes
2answers
172 views

How the best card can I choose?

Me and Varun playing a game of cards (standard deck of 52 cards). In which we distributed 5 cards to each other. Edit: We have seen each other's cards. We have to put the cards in a line one by one ...
8
votes
1answer
255 views

Named after - card puzzle

(this is a picture puzzle) Hint is -'Named after'
12
votes
1answer
239 views

A retroanalysis problem in bridge

This is an entry into the 29th fortnightly topic challenge - Retrograde Analysis. You're passing a bridge table when one of the players (South) is called away suddenly. He gives you his hand and says ...
6
votes
4answers
1k views

6 Cards, Top to Bottom

The six cards shown below were turned face down, "shuffled" (i.e.. re-arranged), and put in a pile, one on top of each other. Each card has an obvious numeric value. In addition, the "J", "Q", and ...
16
votes
10answers
3k views

5 people each have 5 equal cards

A competent logician is playing cards with four of his friends, so that there are a total of 5 people sat around the table. Each player has the same 5 cards, showing A, 2, 3, 4, and 5 (Ace being low). ...
17
votes
6answers
1k views

Unique representation ID for 5-card poker hand using combination without sorting

There is a deck of 52 playing cards (e.g. poker cards). Assign every card a unique number (ID) at will. Every combination of 5 of these cards (a "hand") shall be represented by a unique result number, ...
4
votes
3answers
533 views

Dr. G's Interesting Theorem on Playing Cards

Dr. G has spent his last weekend with analyzing $n$ number of cards which are numbered from $1$ to $n$. He has a fair shuffling machine for his cards and while playing and drawing some cards, he uses ...
4
votes
2answers
255 views

Optimal solution to a modified poker game

Note: Knowledge of the poker game Texas Hold-em is (probably) needed in order to answer this question. You and a friend (only two people are playing) are playing a standard game of Texas Hold-em but ...
4
votes
2answers
329 views

Card Passing Game

13 friends are sitting around a table. They shuffle a half-deck of cards, consisting of only the black cards of a standard deck, and deal out two cards to each person. There are then a series of ...
3
votes
1answer
178 views

Gambling with the gambler [closed]

You are walking on the street and notice a guy gambling with some other guys and you start to watch. The game principle is pretty easy. There is a standard 52-card deck and it is being shuffled every ...
9
votes
1answer
222 views

2 of 4 cards for 1 die

These are equivalent to using using a deck of 4 cards to emulate a 6-sided die. A. Assign integer values to   a, b, c, d   so that the 6 possible &...
4
votes
3answers
1k views

In a Guess The Color game, what's the optimal strategy?

Here's a one-player card game: We begin with a shuffled card deck The player try to guess the color of the card at the top (black or red) If the player guess right, he can keep the card. Else the ...
11
votes
1answer
1k views

Find the winning strategy for this card game

Nine cards numbered 1 through 9 are kept facing up on a table. Alice and Bob are playing a game wherein they pick up cards one at a time, alternatively. The first person to have three cards with sum ...
2
votes
1answer
586 views

Optimal game of Bluff (not the wikipedia one)

Rules Basics 52 well shuffled cards are dealt equally to both players. Player 1 starts the first hand. The game consists of a number of rounds, which are played as follows. On each round, players ...
5
votes
2answers
289 views

Random Shuffled Deck of Cards

It is known that 7 random riffle shuffles are enough to make almost every configuration equally likely in a deck of 52 cards. Perfect Shuffle is when you cut the cards exactly in half and perfectly ...
5
votes
3answers
366 views

Five-hand poker

Both players are dealt $26$ cards from a regular $52$ card deck. He discards $1$ and makes $5$ hands (from the remaining $25$) in any order, each with $5$ cards. His score is given by the sum of ...
14
votes
7answers
2k views

Poker and a card shark

I am playing poker with three friends and from a well-shuffled deck we have each been dealt five cards. I have a hand consisting of the four kings and the two of hearts. Being a poker wizard I know ...
7
votes
1answer
790 views

How To Split The Deck

I took a standard 52-card deck and split it into two piles. Pile 1: Clubs: A 3 5 6 7 8 9 Diamonds: 7 Hearts: A 3 5 6 7 8 9 Spades: A 3 5 6 7 8 9 Pile 2: Clubs: 2 4 T J Q K Diamonds: A 2 3 4 5 6 8 9 ...
3
votes
3answers
559 views

A poker player, a telepath and a clairvoyant

There are three poker players, who are playing heads-up against each other. One of them is a usual poker player. Another - a telepath, who can read thoughts. So if you know your cards, he knows them ...
4
votes
2answers
733 views

Five Card Magic Trick with $N$ card Deck

Last week, I saw a magic show, and was the volunteer for climactic act. The magician introduced this act by talking about the Fitch-Cheney card trick, but then explained that she was going to do an ...
5
votes
6answers
1k views

Three Cards Trick [closed]

Do you know The Fitch Cheney Five Cards Trick? The following is a much harder twist of it. Standard 52 cards deck. Magician is outside the room. Assistant asks random guy from the public to shuffle ...
9
votes
3answers
2k views

How to cheat at cards

I have a deck of 52 cards on the table in front of me, in random order, each one randomly facing either up or down. I place one joker at each end, each of these again randomly facing either up or down,...
-1
votes
3answers
195 views

Who is the liar?

Three friends are playing a game of memory, there are a total of 20 cards with 10 card pairs. They try to make the most pairs in a row, after everyone had a turn they make the following statements: ...
32
votes
4answers
3k views

Multilayer Image Steganography

Alice, Bob, Carol, and Dan are playing a card game. After they all show their cards, Bob notes that by exchanging two cards the order of the players would be reversed; that is, the player with the ...
2
votes
4answers
1k views

4 player card game, who has advantage? [closed]

Edit for "off topic" "correction". I don't know why this question was considered "off topic". It seemed to draw a lot of attention. The "puzzle" was to figure out which person has the advantage ...
4
votes
1answer
308 views

Mathematical probability with cards

A box contains 900 cards enumerated from 100 to 999 (Each number appears once and just in one card). I took some random cards without looking at them and calculated the additions of the digits in each ...
6
votes
2answers
503 views

Solitaire Puzzle

This one shouldn't be too hard. Preparation stage: Take a shuffled deck of standard playing cards and deal 13 face-down piles of 4 cards each. Pick up each pile, arrange the order of the cards ...
7
votes
2answers
752 views

Cooperative guessing against an evil god

Following this: Cooperative guessing game: A standard deck of 52 cards is shuffled and split into two piles of 26 cards each. Two players cooperate, they must score as many tricks as possible. ...
13
votes
4answers
978 views

Cooperative guessing game

A standard deck of 52 cards is shuffled and split into two piles of 26 cards each. Two players cooperate, they must score as many tricks as possible. The first player draw 5 cards from the first ...
7
votes
2answers
1k views

The Great Houdini's awesome card guessing trick (3)

The Great Houdini is performing again! Houdini has built up lots of reputation by showing his great card guessing tricks in [predecessor puzzle-1] and in [predecessor puzzle-2]. Everybody wants to see ...
8
votes
5answers
1k views

The Great Houdini's awesome card guessing trick (2)

The Great Houdini is performing again! Everybody wants to see the famous magician and the magic show is sold out. Today Houdini shows the following sophisticated trick: A guy from the audience ...
5
votes
3answers
814 views

The Great Houdini's awesome card guessing trick (1)

The Great Houdini is performing again! A guy from the audience arbitrarily chooses $52$ cards from a huge stack. He shuffles the cards and announces to Houdini that there are $a$ spades, $b$ hearts, $...
9
votes
2answers
1k views

The Fitch Cheney Card Trick Extended

First, here is the original question which was also discussed here in Puzzling Beta: This is a two-person card trick. At the initial stage, the magician leaves the room. The magician's assistant ...
16
votes
8answers
1k views

Rigged casino that prevents pairs

This question is still active as the answer from @Sleafar has just arrived. Not yet solved. Scenario The heads of 3 top terrorist organisations are planning to play an extremely high-stake poker ...
40
votes
5answers
22k views

A five card trick - How does it work?

At a party last night, my friends Alice and Bob did a magic trick. Any ideas how it worked? Alice shuffled a pack of cards, and asked me to take five. I looked at them. She put the rest of the pack ...
4
votes
3answers
906 views

A game of Green Jack

NB: This is based on a puzzle over at BrainBashers.com. The setup You and a friend play a card game called Green Jack. The deck consists of 16 cards, divided into 4 cards in 4 colors (standard ...
-2
votes
5answers
3k views

How many Questions will you need to Guess the Card?

Suppose your friend grabs a random card from a deck. Now you can ask questions about that card. You can only ask yes/no and greater/less than questions. How many questions do you need to determine the ...