Questions tagged [strategy]

A puzzle whose solution is a methodological plan of action for realizing a specific goal.

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6
votes
2answers
863 views

Non-Greedy Chocolate Eaters

A variant of Greedy Chocolate Eaters (created by my significant other, who doesn't like chocolate all that much) Alice and Bob are playing a game with a rectangular bar of chocolate scored into $m \...
6
votes
1answer
269 views

Russian Roulette (Redux!)

You are challenged to a game of Russian roulette with a six-chamber revolver, but you and your opponent are allowed to change the outcome of the game in different ways. Here's how the game will ...
6
votes
1answer
172 views

A pile of chips involving primes

Ann and Bob play alternately on a pile of chips. On each play, either 1, 2 or 3 chips can be removed except if the number of chips is a prime number. In that case either 1, 2, 3, 4 or 5 chips can be ...
6
votes
3answers
730 views

Another Ebbozonian coin weighing puzzle

This puzzles continues "The Ebbozonian coin weighing puzzle" from last week. In the country of Ebbozonia, there are only two type of coins: light coins and heavy coins. The weights of these coins ...
6
votes
3answers
1k views

Ten unspeakable words

I wrote the following puzzle a couple of years ago. Since I no longer remember the solution, I feel it's a good enough puzzle to share. On accusation of littering, you and your assistant are ...
6
votes
2answers
464 views

Placing dominoes on a 3x100 checkerboard

Alice and Bob play a game by alternately placing dominoes on a $3\times100$ checkerboard (3 rows, 100 columns). Alice has the first move. A move of Alice consists in placing a $1\times2$ (horizontal) ...
6
votes
1answer
498 views

Arranging cards in rows

This question appeared in an old math contest, and I seem to remember that the answer I had back when I first saw it was unsatisfactory. You have a deck of cards numbered from $1$ to $60$. First, ...
6
votes
1answer
254 views

Magic: the Gathering – The end of time

Thanks to NeedAName and his latest Magic: the Gathering Challenge I actually noticed there is a magic-the-gathering tag. It was quite some time ago that I played Magic the last time, but nevertheless ...
6
votes
3answers
600 views

Two Sheriffs and Eavesdroppers - 2

“The Two Sheriffs” puzzle was already discussed here Two Sheriffs and Eavesdroppers. This puzzle has only one difference: we have seven suspects instead of eight. Two sheriffs in neighboring towns ...
6
votes
2answers
399 views

Jewels in the box

Professor Egghead participates today in a local game show. There are six jewels (a diamond, an emerald, a moonstone, a ruby, a sapphire, and a topaz), and there are six boxes that carry the numbers 1,...
6
votes
1answer
243 views

Dividing the gold

There is a king and 3 women in a castle. One day, the king give 3 women a total of 100 golds. He said that each woman can propose an idea to share the gold among themselves. If the proposal passed ...
6
votes
2answers
209 views

You Sign Me Right Round (Extended Edition)

I wanted to ask more questions about variations on This Problem. If you hadn't seen that one, check it out. It's required reading (and probably more fun). In the original problem, these were the ...
6
votes
2answers
537 views

Hopping Frogs puzzle variant

There is an old puzzle which has various names such as Toads and Frogs, Jumping Frogs, Hopping Frogs, Leap Frog, etc., and which has been asked here before. I'd like to share a variant of this puzzle ...
6
votes
2answers
511 views

Block the snake from reaching points

Solution for Version 2 pending.... There is a $100\times 100$ grid. The upper left corner has coordinates $(1,1)$ and bottom right corner has $(100,100)$. A 'snake' starts by occupying a single cell ...
6
votes
1answer
217 views

I'm a Proper Divisor

Ann and Bob are playing a number game. Ann starts with the number 60. Then she subtracts a proper divisor of 60 from it. Bob then takes the number Ann made and subtracts one of its proper divisors ...
6
votes
3answers
381 views

The Alchemist's brew

I'm an Alchemist and I want to prepare Universal Panacea. That's a precious thing and I will be able to sell it for good money. The complete recipe for the Panacea is of course very complex (and ...
6
votes
1answer
310 views

Maximize all weights

This question is related to What's the fewest weights you need to balance any weight from 1 to 40 pounds? You had 4 weights to balance any weight from $1$ to $40$ pounds which is answered previously ...
6
votes
2answers
756 views

The Fanatic Fever(twist on the 5 pirates puzzle)

While raiding a tropical island, 6 pirates have an incredibly unlucky day. While they scoured the island in search of treasure, one of them was infected with the Fanatic Fever, a disease which hits ...
6
votes
1answer
487 views

Capture The Stones

This puzzle was created by me as a single-player variation on the game of go. The objective here is simple: capture all 41 grey stones on the board below in the least number of moves. Just like in ...
6
votes
2answers
675 views

Crystal Maze totem pole puzzle

The UK game show "The Crystal Maze" features a puzzle based around a totem pole. The contestant has four different coloured blocks which can be stacked up to make a totem pole. The blocks may be ...
6
votes
1answer
396 views

Checkers Against The King

The king has invented a new game called King's Checkers. The rules are simple, it's exactly like regular Checkers, the only difference? The king plays first and all his pieces are automatically "king",...
6
votes
1answer
975 views

Frying Three Steaks

You invite your friend to the dinner. so you would like to prepare 3 fried steaks but you do not have much time to cook. You are trying to figure out how to cook all steaks perfectly (fried and ...
6
votes
2answers
460 views

Twilight Zelda Guardian Puzzle

I'm playing a game (see here), and in it is a puzzle, which I've made a TIKZ graph seen below for illustration: $\hspace{2.5cm}$ There is one player. The player ($\mathscr{L}$) moves from node to ...
5
votes
7answers
651 views

The selling of the sheep [closed]

I do not know the answer to this puzzle, and I found it in some old files I had Many years ago, there was a shepherd with 3 children. One day, while talking to the owner of the herd, the shepherd ...
5
votes
5answers
427 views

Russian roulette

You are challenged to a game of Russian roulette. Your opponent places two bullets side by side in a six chamber revolver and spins the chamber. She explains that the game is single turn-based and ...
5
votes
2answers
719 views

A prime number game

Alice and Bob play the following game on a $9\times11$ chessboard. First Alice divides the chessboard into $33$ smaller rectangles of dimensions $1\times3$ and $3\times1$. Then Bob labels each of ...
5
votes
3answers
1k views

Hacking an electronic keypad v2

This is related to Hacking an electronic keypad. You are a spy trying to break into an enemy facility. The back door is protected by an electronic keypad lock. You know that this particular lock is ...
5
votes
3answers
402 views

Removing green marbles from the table

Alice and Bob play the following game that starts with $N\ge3$ green marbles on the table. Alice and Bob move alternatingly. Alice makes the first move. In this first move, Alice removes $x$ green ...
5
votes
2answers
722 views

How much money can we make? v2

This is follow up question to How much money can we make? My five friends and I used to loan each other money all the time. But over the past several years we have moved apart. We don't trust ...
5
votes
3answers
2k views

Guessing a number game with a twist

Most of us have come across the problem in which a player chooses a number within a range $1-n$ and we have to guess that number by asking minimum no. of questions. That can be done by binary search(...
5
votes
5answers
515 views

Identify who is who between 3 persons who tell the truth and lie alternately

Dipsy tells the truth in 1 day and lies in the next day alternately. If today he tell the truth, tomorrow he will lying, 2 days later he will tell the truth, and so on. Lala tells the truth in 2 ...
5
votes
3answers
989 views

Strategy for Modified Lights out

A friend of mine showed me a variation of lights out that they were interested in, and asked me if it would be possible to solve any given empty grid. This variation involves toggling not just the ...
5
votes
2answers
266 views

The Wires Underground [duplicate]

There are ten wires that run underground across a river. Thus on each of the banks, there are ten ends of the wires. Unfortunately, given an end of a wire on this bank, one doesn't know which end on ...
5
votes
1answer
337 views

Another Secret Polynomial

Alice: Let's play a game, Bob! Bob: (sighing) What is it this time? Alice: I'm thinking of a polynomial $P$ with integer co-efficients. For any integer $n$, you can ask me what $P(n)$ is. Then, if,...
5
votes
2answers
192 views

Pick and roll and guess

The caretakers in a Home for the Golden Agers decided to have a guessing game for the old fellows. Two partner teams shall play the game and the winners shall have free access to the fridge for 1 week....
5
votes
3answers
264 views

Crazy queen in checkers

Checkers Checkers, also called draughts, is an interesting game. all pieces are placed on black tile and are all pawns at the start. When a pawn reach the final line, a powerful piece is created: the ...
5
votes
3answers
485 views

“Alien Love” Puzzle

There is a group of 10 aliens and each alien is either male or female. You don't know how many male or female aliens are in the group, but you know that exactly one of them is a "hybrid" male alien. ...
5
votes
3answers
892 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, $...
5
votes
2answers
119 views

A pile of chips involving powers of 2

Ann and Bob play alternately on a pile of chips. On each play, any number of chips, which is a power of 2 (including 1=$2^0$), can be removed from the pile. Obviously the number of chips to be removed ...
5
votes
2answers
589 views

Lead the murderers out

Imagine you are in a big hall. Except you, there are 20 other people. In the beginning, you have different pieces of paper: ...
5
votes
1answer
493 views

Optimal Building Strategy Puzzle

Suppose a general is in charge of a mining site with 5 workers and he has a total of 50 units of gold. Each worker is able to mine for him 40 units of gold per minute. The general is able to ...
5
votes
3answers
508 views

Foolproof double betting

Just made up a problem. Have ideas, but no proof yet – came here for professional help. Tonight an important match of Metagame (box/football/baseball/chess) takes place. Everyone is hyped. Everyone ...
5
votes
4answers
491 views

Time traveler treasure Hunt

A time traveler is collecting treasures. He is using a space-time ship to transport between 5 different place-rooms. Each place has 1 precious treasure from the ancient times in each of 5 time zones. ...
5
votes
2answers
403 views

The Punic Wars are back!

The Roman Empire is at war with Carthage. Hannibal's army is composed of $a$ archers, $b$ ballistae, $c$ cavalrymen, $d$ dart-shooters, $e$ elephants and $f$ fighters. In each round of the battle, ...
5
votes
2answers
411 views

Land claim staking

It was traditional during the times of the Oregon Trail and the gold rush that men founding new towns were allowed to stake their claim on land upon arriving to the west coast. Suppose a man is ...
5
votes
2answers
212 views

How do I choose between letter possibilities for 2- and 3-letter words in a cryptogram?

I've tried to begin solving a cryptogram by making educated guesses from the context: position of punctuation, the presence of single-letter words, or assumptions about the frequency of the letter E, ...
5
votes
1answer
492 views

What will be the last Sudoku number to be filled?

When I am completing a Sudoku puzzle, there are always two last numbers to fill. Maybe it is just my puzzle solving approach or maybe it is inherent to Sudoku. I got wondering, would everyone who ...
5
votes
3answers
286 views

Dots and Boxes Part 2- Best Move in Given Position

This is a follow-up to my first Dots and Boxes question. It is just a little bit harder than the first one. Each one I post will be a bit harder than the previous one, and they will all be from games ...
5
votes
2answers
213 views

Arranging a long line of cards

Annie has a very long line of cards, numbered from 1 to $n$, such that every odd card is face-up and every even card is face-down. The only way she can modify the line is by taking any segment of ...
5
votes
1answer
276 views

Find k defective balls out of n balls

There are $n$ balls out of which $k$ are defective, where $k<n/2$. All defective balls have the same weight $w$, and all non-defective balls have the same weight $v$ with $v<w$. Determine all ...