
1. 
pretorik 
 
161 
2. 
Gordon Weir, markr 
 
104 
3. 
mbloomfi 
 
97 
4. 
Dennis Nazarov 
 
96 
5. 
zzz123 
 
72 
6. 
lidSpelunker, Srikanta 
 
53 
7. 
SAMIH FAHMY 
 
48 
8. 
jkr 
 
44 
9. 
EroOO 
 
39 
10. 
sunday 
 
38 




1. 
denisR, mishik 
 
236 
2. 
alan, De_Bill 
 
231 
3. 
dddfff 
 
228 
4. 
kavfy 
 
221 
5. 
idler_ 
 
106 
6. 
akajobe 
 
94 
7. 
tolstyi 
 
56 
8. 
STARuK 
 
42 
9. 
vale 
 
31 
10. 
xandr 
 
11 





Place numbers 1,2,.., 9 without repetitions into a 3x3 square so that
the sums in all rows, columns, and diagonals are all equal. 


Puzzle statistics "Numbers in a square".
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A Megamind has ordered a set of steel balls for his scientific
experiments: 2 red, 2 orange, 2 yellow, 2 green, and 2 blue.
The order was fulfilled but the balls of some color were made 1g
lighter than the others. The Megamind has a balance scale
that shows the exact weight differential between the two cups. He
needs to determine the defective color using one weighing.
Please, help the Megamind to do this. 


Puzzle statistics "Defective balls".
Last updated 1618816.8 minutes ago.

Solved by: 22
Daily average: 0.01
Answers submitted: 24
Viewed by: 257
Fraction solved by: 8.5%
Solved at first attempt: 95.4%
Average discussion length: 1.1
Liked the puzzle: 7
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0

Links and chains 
Logic puzzles 

Weight: 1 

Liked the puzzle: 100% 

02.04.2011 

Once upon a time, a Megamind worked as a smith. He was brought 5
chains each consisting of 3 links. What is the minimal number of links
that the Megamind should relock to make one long chain? 


Puzzle statistics "Links and chains".
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Two incense sticks 
Logic puzzles 

Weight: 1 

Liked the puzzle: 100% 

27.12.2009 

You have two incense sticks, that burn unevenly, and a lighter. Each
will burn for an hour. How can you time 45 minutes using nothing but
these tools. 


Puzzle statistics "Two incense sticks".
Last updated 1618816.8 minutes ago.

Solved by: 41
Daily average: 0.02
Answers submitted: 53
Viewed by: 296
Fraction solved by: 13.8%
Solved at first attempt: 92.6%
Average discussion length: 1.1
Liked the puzzle: 11
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0


A bottle,a glass, a carafe, and a can contain milk, lemonade,
water, and coke. Water and milk are not in the bottle. The container
with lemonade is immediately between the carafe and the container with
coke. The can does not contain lemonade or water. The glass is next to
the can and the container with milk. The containers form a row. How
exactly are they arranged? 


Puzzle statistics "Milk, lemonade, water, and coke".
Last updated 1618816.8 minutes ago.

Solved by: 19
Daily average: 0.01
Answers submitted: 21
Viewed by: 259
Fraction solved by: 7.3%
Solved at first attempt: 78.9%
Average discussion length: 1.4
Liked the puzzle: 4
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A Megamind walked along a fence and discovered strange pairs of
numbers. First, he saw "188>4". A bit fаrther, he discovered
"232>0". A few steps after that, "100>2". Then, "163>1". Then he
saw a little boy who was just beginning to paint something. When the
Megamind called a boy, he ran away. Approaching the site, the Megamind
saw an incomplete pair "386>...". He took out his favorite marker and
completed the pair. What number did he write? 


Puzzle statistics "Numbers on the fence".
Last updated 1618816.8 minutes ago.

Solved by: 20
Daily average: 0.01
Answers submitted: 22
Viewed by: 295
Fraction solved by: 6.7%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 9
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0


A Megamind is lost in the mountains. He is standing on a path,
shouting for help.
Finally, he sees a local approaching. Megamind knows that the locals
can be knights that always tell the truth, or knaves that always lie.
He also knows that the path leads to the village of knights in one
direction and to the village of knaves in the other. The problems is
that the knaves are also hateful of Megaminds, and will stone him if
gets to their village. How can Megamind ask one question and determine
the right way to go? 


Puzzle statistics "Two villages".
Last updated 1618816.8 minutes ago.

Solved by: 37
Daily average: 0.02
Answers submitted: 47
Viewed by: 296
Fraction solved by: 12.5%
Solved at first attempt: 83.7%
Average discussion length: 1.4
Liked the puzzle: 11
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What is the minimal number of weights required to be able to balance
all integer weights 1,2,...,40 on a balance scale?
Justify the minimality. 


Puzzle statistics "Weights".
Last updated 1618816.8 minutes ago.

Solved by: 9
Daily average: 0
Answers submitted: 17
Viewed by: 274
Fraction solved by: 3.2%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 2
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50 coins 
Logic puzzles 

Weight: 3 

Liked the puzzle: 100% 

27.12.2009 

Once upon a time, a tsar was holding a reception and the Megamind was
among the guests. The tsar decided to test how smart the Megamind was,
took him into a dark room, and gave the following task: On the table
in this room, there are 50 coins, exactly 10 of them are tails up. In
the darkness, it is impossible to determine the sides of these coins.
Touching the coins also does not help. The Megamind has to separate
these coins into two groups so that the number of tails in both are
equal. Can he do it? 


Puzzle statistics "50 coins".
Last updated 1618816.8 minutes ago.

Solved by: 22
Daily average: 0.01
Answers submitted: 30
Viewed by: 296
Fraction solved by: 7.4%
Solved at first attempt: 90.9%
Average discussion length: 1.2
Liked the puzzle: 8
Did not like the puzzle:
0


The set of numbers 1,3,8,120 has a remarkable property: the product of
any two numbers is a perfect square minus one. Find a fifth number
that could be added to the set preserving its property. 


Puzzle statistics "The fifth number".
Last updated 1618816.8 minutes ago.

Solved by: 37
Daily average: 0.02
Answers submitted: 41
Viewed by: 291
Fraction solved by: 12.7%
Solved at first attempt: 97.2%
Average discussion length: 1.1
Liked the puzzle: 11
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0

Six matches and triangles 2 
Geometry puzzles 

Weight: 4 

Liked the puzzle: 100% 

07.02.2010 

How to make one equilateral and three isosceles (and not equilateral!) triangles using 6 sticks of the same length? Sticks cannot be broken and/or laid over each other and no free ends of the matches may be left. 


Puzzle statistics "Six matches and triangles 2".
Last updated 1618816.8 minutes ago.

Solved by: 5
Daily average: 0
Answers submitted: 15
Viewed by: 273
Fraction solved by: 1.8%
Solved at first attempt: 40%
Average discussion length: 2.2
Liked the puzzle: 3
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After a shipwreck, a MegaMind found himself on an island where some natives always lie and some always tell the truth. As a ritual, all natives stood in a circle facing the center, joined their hands and everybody told the MegaMind whether his right hand side neighbor is a liar or a truthteller. Based on this information, the MegaMind was able to determine the exact percentage of natives that tell the truth.
Can you also determine this percentage? 


Puzzle statistics "A circle of lies".
Last updated 1618816.8 minutes ago.

Solved by: 9
Daily average: 0
Answers submitted: 10
Viewed by: 284
Fraction solved by: 3.1%
Solved at first attempt: 77.7%
Average discussion length: 1.8
Liked the puzzle: 2
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A game of symmetry 
Games puzzles 

Weight: 4 

Liked the puzzle: 100% 

17.03.2011 

Two megaminds play a game on a board sized 1x81 cells. The board is initially empty.
At each turn first megamind can place a stone (either black or white) in any cell. Second megamind can either swap any two stones or skip a turn. After megaminds made 81 turns each, the symmetry of the board is assessed. If the stones are located symmetrically, second megamind wins, if not  first one wins. Who will win and why? 


Puzzle statistics "A game of symmetry".
Last updated 1618816.8 minutes ago.

Solved by: 3
Daily average: 0
Answers submitted: 4
Viewed by: 35
Fraction solved by: 8.5%
Solved at first attempt: 66.6%
Average discussion length: 1.3
Liked the puzzle: 2
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The telephone cable 2 
Geometry puzzles 

Weight: 5 

Liked the puzzle: 100% 

01.01.2010 

The Megamind has a square parcel of land of size 1x1 km. Accidentally, he has found out that the devious Occupants had buried a telephone cable through his land and use it for their devious communications. The cable is buried along a straight line crossing the square land plot. After discovering this, the Megamind got his shovel and... paused to think. What is the shortest trench that the Megamind has to dig to find the cable? The trench may be disconnected. The proof of optimality is not required. 


Puzzle statistics "The telephone cable 2".
Last updated 1618816.8 minutes ago.

Solved by: 8
Daily average: 0
Answers submitted: 15
Viewed by: 295
Fraction solved by: 2.7%
Solved at first attempt: 75%
Average discussion length: 3.6
Liked the puzzle: 4
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0

Caesar and Brutus 
Games puzzles 

Weight: 5 

Liked the puzzle: 100% 

26.12.2009 

Two commanders (Caesar and Brutus) conquer a country which forms a connected graph with nodes representing cities and edges representing roads. First, Caesar chooses a city and claims it. Then, Brutus claims any of the remaining cities. Turn by turn, the commanders claim the available cities that are adjacent to the cities they have already claimed. If a commander cannot make a claim, he skips a move. The game continues until all cities have been claimed. Both commanders wish to claim a maximal number of cities. Can Brutus win in this game? 


Puzzle statistics "Caesar and Brutus".
Last updated 1618816.8 minutes ago.

Solved by: 3
Daily average: 0
Answers submitted: 4
Viewed by: 296
Fraction solved by: 1%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 1
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You are standing at the road fork. One of the two roads leads to your
destination, but you don't know which one. Fortunately, there is a
sentry guarding the intersection. Unfortunately, the sentry can be a
knight or a knave, moreover, he is a foreigner. He understands you,
but when he responds, he says "uhh" or "err" meaning "yes" or "no",
but you don't know what means what. He does not say anything else, and
he is standing at attention, not being able to point in the right
direction. On top of all this, the sentry is somewhat dumb, i.e. he
cannot understand sentences longer than 13 words. You may ask a single
question to figure out which way to go. Which question should you ask? 


Puzzle statistics "A foreign sentry".
Last updated 1618816.8 minutes ago.

Solved by: 6
Daily average: 0
Answers submitted: 8
Viewed by: 293
Fraction solved by: 2%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 3
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0


