This tag is meant for questions about the mathematical principles behind games, riddles, or their possible solutions. If the answer is known to you please do not use this tag to "riddle" other users, but rather to ask about the correctness of a possible solution or ways to extend and improve an ...

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6
votes
2answers
158 views

How many archers do I need to deploy to destroy an Archer Tower?

I was playing Clash of Clans and came across this interesting problem. Consider the case when I'm attacking an enemy war base with an Archer. My archer can cause a damage of 12 hitpoint per second. ...
1
vote
2answers
52 views

economist puzzle for

Mr. White and Mr. Black agreed on the plan to average the wealth by pairs of economic classes, but they differed on the order. Averaging means that the total wealth of the two classes is ...
2
votes
0answers
70 views

Math puzzle I have been stuck on

Have had this math puzzle that I have been unable to solve for a while. Each leter is a number between 1-9. No letter uses the same number twice (aka if B is 3 D can't be 3 also). The ? mark ...
2
votes
1answer
62 views

Difficult sequence puzzle

What is the 25$^{th}$ term of this infinite sequence? $$1,1,1,1,1,691,2,3617,...$$ I have tried for an hour now and I can't find any meaningful relation between the terms.
4
votes
3answers
331 views

Just a 3rd grade math problem in my country. Please help.

Even though this is a 3rd-grade math problem, people found it extremely hard. Any people have a solution, or algorithm is welcome. I'll try make a program base on the algorithm and see if it's ...
3
votes
2answers
28 views

Searching specific numbers based on clues

"Find x for 0≤x≤100,000." My clues are as following. I'm not sure whether there are multiple answers or that only one 'x' remains based on these clues: This number isn’t between 20,000 and 40,000 ...
-1
votes
0answers
41 views

A Number Puzzle [closed]

Can someone help me to solve this puzzle. Please post the logic as well. Thanks.
7
votes
0answers
52 views

Diagonal-free Sudoku grid

I have a Sudoku grid with the property that diagonally adjacent elements are distinct (it is also a torus under the same property). The grid offers new and exciting logical possibilites. My question ...
2
votes
2answers
97 views

The Efficiency of Random Parking Problem

A few days ago in my Calculus BC class we were given a page of 6 challenging end of the year problems. That was a refreshing change from the drudgery we usually do (WebAssign). One of them went like ...
0
votes
0answers
45 views

Not so obvious probability puzzle.

You are given two boxes with a number inside each box. The two numbers are different but you have no idea what they are. You pick one box to open; read the number inside; and then guess if the number ...
1
vote
1answer
32 views

Recursive Hexagon Problem to find number of hexagons at each stage

The source of this problem is this SPOJ question. Let me simplify it: A valid beehive is recursively defined as follows: 1. A single regular hexagon is a valid beehive. 2. To all the external cells of ...
2
votes
3answers
127 views

logic puzzle (truth-tellers / liars)

I am trying to solve this puzzle. It is supposed to be solvable. There are 3 people A,B,C. One of them is always lying, one of them is always telling the truth and one of them is always answering ...
2
votes
0answers
81 views

ZELDA Guardian Puzzle Part II - Shortest Path (Unsolved for new rules)

This question is in relation to the following previously asked question: Twilight Zelda Guardian Puzzle : Shortest Path (UPDATE: ADDED RULES) A 1-step-less solution was uncovered, but under an ...
1
vote
3answers
38 views

Find a possible pair of numbers given HCF and a factor of the LCM

I was just going through a GCSE paper with a student and I came across a question that I'm struggling to find a good method for. The question was this: Martin thinks of two numbers. The ...
0
votes
2answers
108 views

A mathematical puzzle

I am given a set $S$ of sorted numbers and I have to find value of $rndm(S)$ $$\Large rndm(S)=\sum_{s\text{ is a subset of }S}\max(s)-\min(s)$$ Where $\max(s)$ represents the maximum value in set ...
2
votes
4answers
96 views

Logical puzzle. 3 Persons, each 2 statements, 1 lie, 1 true

I got a question at university which I cannot solve. We are currently working on RSA encryption and I'm not sure what that has to do with the question. Maybe I miss something. Anyway, here is the ...
0
votes
3answers
43 views

How is this true? Bookworm puzzle

This is from Eugene Northrop's book Riddles in Mathematics. Why is the answer 1 inch. Iit should be three. What logic am I missing here?
1
vote
1answer
43 views

Is the puzzle logically (or in some other way) correct?

There are 30 metereologists working in their laboratory making predictions about the weather for the next day. They say either "Tomorrow will be sunny" or "Tomorrow will be cloudy". One of the ...
0
votes
1answer
51 views

What question to ask to find right path

Suppose a certain country is inhabited by truth teller and liars, who only respond to yes or no questions. A tourist comes to a fork in the road where one branch leads to the capital, and the other ...
0
votes
0answers
63 views

Best Math to learn for logic problems?

I have a friend who can do any Math logic puzzle in a few seconds. The ones where they ask about for e.g. the one with monkey and coconuts or guys at the bar taking and giving each other change. A ...
1
vote
2answers
52 views

Can you find the lighter and heavier marbles?

You have $10$ bags with marbles. Each bag has $2000$ marbles. Standard marbles weight $10$g. However, one bag has marbles that all weight $9$g and one bag has marbles that all weight $11$g. If you can ...
0
votes
1answer
31 views

Nontechnical Proof of “Puzzle on coins: Designing an operation”

Previously asked: A square table has a coin at each corner. Design an execution sequence, each of whose steps consists of one of the following operations: ONE (O): The operation ...
0
votes
0answers
47 views

find chair in survivor problem

Complete Question Text: Take a second to imagine that you are in a room with 100 chairs arranged in a circle. These chairs are numbered sequentially from One to One Hundred. At some point ...
1
vote
2answers
35 views

Shortest distance between two moving points

So I ofund this question on the internet, which turned out more tricky than I thought: " The position of boat A is given by $x(t)=3-t$ and $y(t)=2t-4$ The position of boat B is $x(t)=4-3t)$ and ...
-8
votes
2answers
222 views

?+?+?=30 (1,3,5,7,9,11,13,15) [duplicate]

?+?+?=30 Please slowe this question and reple answer
16
votes
0answers
191 views

What Rubik's Twist configuration has the lowest visible surface area?

The Rubik's Twist has been a fun time sink. From the wiki page, [It] is a toy with twenty-four wedges that are right isosceles triangular prisms. The wedges are connected by spring bolts, so that ...
1
vote
1answer
61 views

the blood test riddle (number theory)

A microbiologist has been given a set of $100$ blood vials. Exact one of those $100$ vials is positive to a concrete disease X. The microbiologist desires to send only $7$ vials for analysis. He can ...
9
votes
2answers
125 views

Finding pattern

Just a puzzle. \begin{matrix} 2 & 9 & ? \\ 11 & 33 & 66 \\ 8 & 3 & 27 \\ \end{matrix} The options are $35$, $40$, $45$, $55$. $45$ is false. I ...
5
votes
14answers
2k views

Measure 11 liters using bottles of 16, 6, and 3 liters

This question has been bugging me for a day and finally I gave up and decided to ask the community for it so here's how it goes: Suppose we have 3 bottles with capacities of $16,6$ and $3$ liters, ...
0
votes
4answers
62 views

How to come up with proofs of these results? Or, are these results true in the first place?

Let $x_n$ and $y_n$ be integer sequences determined by $$x_n + y_n \sqrt{2} = (1+\sqrt{2})^n \ \ \ \mbox{ for } \ n= 1, 2, 3, \ldots. $$ Then how to show that (a) $x_{n+1} = y_{n+1} + y_n$, $\ \ \ ...
5
votes
2answers
115 views

Optimal scheduling dilemma (A textbook math problem IRL)?

I am trying to solve a scheduling problem for a boys camp. I have 12 teams(A through L), 6 sports for them to play, and 6 periods for them to play in(P1 through P6). ...
0
votes
2answers
43 views

Find minimum and maximum wins required in a $8$ team tournament

In a tournament, there are $8$ teams in total and playing against each other $2$ times. We need to find (-)What is the minimum no of wins required to qualify for the next round? (-)What is the ...
11
votes
2answers
300 views

Twilight Zelda Guardian Puzzle : Shortest Path (UPDATE: ADDED RULES)

I'm playing a video game right now and in it is a puzzle (see here). There are solutions to solving it (see here) on the Internet, but I'd like to know if this path is the shortest path (least amount ...
0
votes
0answers
30 views

Formula for coefficient of Mahonian numbers

I recently came out with this article . It tells about triangle of mahonian number.The T(n,k) is coefficients in expansion of Product_{i=0..n-1} (1 + x + ... + x^i), where k ranges from 0 to n*(n + ...
38
votes
7answers
5k views

How many scientists can survive?

Yesterday the aliens took 100 scientists from Earth as prisoners. They want to test how smart the humans are. The aliens made 101 headbands, numbered from 1 to 101. On the contest day, they throw ...
1
vote
1answer
34 views

KenKen puzzles. Minimum number of “clues” to uniquely define nxn grid.

I recently discovered the "KenKen" puzzle and have been trying to figure out some of the mathematics behind it. This led me to the following question: Given an N x N grid, what is the minimum number ...
0
votes
3answers
65 views

Verbal Reasoning (Puzzle)

There are four persons A, B, C and D. The total amount of money with A and B together is equal to the total amount of money with C and D together. But the total amount of money with B and D together ...
2
votes
3answers
231 views

Is it possible to solve the Zebra Puzzle/Einstein's Riddle using pure math?

A coworker of mine posted a problem in our local communication software that seems to be a simpler variation of the Zebra Puzzle/Einstein's Riddle. I know how to solve it intuitively, by using ...
1
vote
1answer
45 views

How to check if the 1st player can always win [closed]

Suppose $2$ people start with a pile of $n$ matches, and each turn each player takes $1$ to $6$ matches from the pile. The player to take the last match wins. Let $n=75$. Can the 1st player always ...
1
vote
1answer
63 views

A simple to explain solution to this kids' geometry puzzle

A smart 10 year old asked me basically this question. Consider a rectangle with both diagonals drawn in. Now ask if you can visit all the edges by travelling from some starting vertex and only ...
4
votes
1answer
74 views

Time and distance: Police and a thief with a twist.

A thief was given a head-start of 15 hour. The velocity of the thief being 4 km/hr and the police chasing after him be 5 Km/hr. A dog is moving to and fro between the police and the thief, starting ...
0
votes
1answer
47 views

Mini Tetris Winning Configuration

So here's the problem: A winning configuration in the game of Mini-Tetris is a complete tiling of a 2 x n board using only the three shapes shown in Figure 1. By allowing rotations, there can be ...
0
votes
2answers
82 views

In the card game “Projective Set”: Compute the probability that $n$ cards contain a set

In the game of Projective Set, it turns out that any seven cards contain a projective set. For fewer than 7 cards, how can we determine the probability that one or more sets exist (in terms of the ...
4
votes
1answer
104 views

In the card came “Projective Set”, show that 7 cards do always contain a set. [duplicate]

In the game of Projective Set, it turns out that any seven cards contain a projective set. How can one prove this? And for fewer than 7 cards, how can we determine the probability that one or more ...
1
vote
0answers
58 views

Real Mathematics in Video Games

Out of curiousity (and perhaps also to amuse my students), I am looking for examples of actual mathematics appearing in video (computer) games. Of course that sort of mathematics would probably be ...
2
votes
3answers
52 views

Number in tens place

A number in tens place in result of $4^{2015} \cdot 9^{2016}$ is? Obviously without using calculator, though I doubt it could count with those high numbers. By tens place I mean, for example if you ...
2
votes
1answer
76 views

What is the _simplest_ way to solve problems of this kind?

Two doors with talking doorknockers - one always tells the truth and one always lies. One door leads to death other to escape. Only one question may be asked to either of the door knockers. What would ...
1
vote
2answers
46 views

Number of boys in school

We have $400$ students in a school. Every $20^{th}$ student failed at the end of the school year. Which was $2\%$ of schools girls and $10\%$ of schools boys. The number of all boys attending the ...
1
vote
2answers
68 views

Number addition riddle

I got this math "riddle" in one of my math test, and I would love to know how to solve it. If $$S = 1 + 2 + 3 + 4 + \ldots + 2015,$$ then a sum of $$1 + 2 + 3 + \ldots + 2015 + 2016 + \ldots + 4030$$ ...
1
vote
1answer
35 views

Number of apples in a basket riddle

You have six baskets with apples - 10,12,15,20,22,25 (this is how many apples there were in them - 10 in first, 12 in second..). Some of the apples are red and some are green. After one basket was ...