Carl Löndahl
  • Member for 6 years, 8 months
  • Last seen more than a month ago
Coffee-break Puzzle: Where does the Driver Sit?
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51 votes

Added an image for clarification:

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A game with 52 cards
19 votes

An upper bound Bob picks a random permutation of the deck and then rotates the subset of his deck that does not match Alice's. The worst case is when the whole deck is a rotation of his initial ...

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The end of the life!
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17 votes

The answer is because that becomes Explantation:

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Mensa IQ test question - shapes in a 4x3 grid
17 votes

Since the answer already has been accepted I would add this as a comment, but I do not have sufficient points to do so. I agree that the answer should be... but due to the reason that...

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Expected Number of Tosses Until H,T,T,H
14 votes

This will require since Here is a graphical representation Here is a simulation import random E = 0 for j in range(0, 20000): s = "" i = 0 while True: i += 1 s += ...

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Continue the Pattern #6 Fractions of Circles
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13 votes

If we consider them to be Here is an image

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Professor Halfbrain and the 99x99 chessboard (Part 1)
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11 votes

This is a sketchy proof of what Ivo suspected in the comments. Take an arbitrary selection as below. $A+B+E+F = 0$ $A+B+I+K = 0$ $=> E+F=I+K$ $E+F+I+K = 0$ $=>E +F = -I-K$ $E = -F$ $I = -...

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Pattern Recognition Puzzle
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10 votes

I believe it is Since

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What loves to talk but has little to say
9 votes

This is a long shot but here goes... What loves to talk but has little to say Nags you in the morning and throughout the day

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The square of 1514
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9 votes

I am the square of 1514, but actually, I'm just the square of 4. I possess a property, where women could be burned for in my time

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05132: Some off facing?
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9 votes

The numbers correspond to The phrases are The complete list: They are ordered by

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What is the missing item that completes the pattern?
8 votes

Because:

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Draw the item after decoding the instructions
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8 votes

4 is partly covered by 0 0 is completly covered by 3 6 is partly covered by 0 6 is partly uncovered by 0 4 is completely uncovered by 6 4 is partly uncovered by 3 6 is not covered by 4 So we need a ...

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Weighing in 89 different ways
8 votes

Turns out there are two solutions: $171$ and $341$ (unless I made a terrible mistake; I have checked this using some Python code). L = [1,2,4,8,16,32,64,128,256,512] Q = [0]*(sum(L)+1) def rec(Q, L, ...

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Changing baby's shirt
7 votes

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Switch the Odd One Out
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7 votes

This gives

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Whats your favourite number?
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7 votes

Possible answer: Because Example

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Weighing in 2015 different ways
7 votes

Update Going back to my original post where $f$ is defined as This is explained as follows: Let $*****,y_1,y_2$ be an arbitrary number. If $y_2$ is 0, this cannot be further expanded. So we ...

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Magic Numerical Equations
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7 votes

or Therefore, Of course, there are many possible solutions to this question...

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6 - the magic number (version 2)
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7 votes

10. 11.

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Another Rebus! Guess the Common Theme and Solve!
6 votes

E:

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Grandma's cipher
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6 votes

The word is since she

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

Here is another take. We can use the modulus $53$ using only operations $(+,-,x)$, simply by removing $53$ until we have reached a non-negative number strictly less than $53$. Let $a,b,c,d,e \in \...

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Seven cowboys play a coin tossing game
6 votes

Making the events independent, we get a probabilty that is $p_{i,j} = \mathbb{P}(\text{player }i\text{ wins }j\text{ games}) = {6 \choose j}\cdot 2^{-6}$. (note: if six players wins 3 games, then ...

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The Code that's not a Code
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6 votes

The answer is which is encoded as

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A jar of mixed coins
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6 votes

The probability is given by $P(fair|heads^m) = P(heads^m|fair) \cdot P(fair) / P(heads^m)$, where $P(heads^m) = P(heads^m|fair)\cdot P(fair) + P(heads^m|nonfair)\cdot P(nonfair) = 1/2^m \cdot K/N + 1^...

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A prolific nine-letter word
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5 votes

The question did not state no computers, so I guess this answer is as good as any other. ...gives... which gives a score of 389. This is using the Merriam-Webster dictionary. No word is an anagram ...

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IQ test question-black and white squares
5 votes

The answer is probably since the boxes move as follows ...at least that pattern matches and it is reasonably simple.

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Two puzzles about encompassing convex sets
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5 votes

Here is a somewhat sketch proof for (1) that may be missing some less obvious details: Some graphical example: So... For (2) even sketchier... Some more badly-drawn graphics: To...

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Malcolm Gladwell's Outliers - Progressive Matrices Puzzle
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5 votes

I mapped the symbols to $\{0,1,2\}$, so we get: 011 | 221 | 022 001 | 120 | 011 222 | 001 | 120 ----------------- 210 | 210 | 210 212 | 201 | 122 001 | 120 | 010 ----------------- 020 | 012 | ...

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