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| 1. |
markr |
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100 |
| 2. |
monkeyspike |
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28 |
| 3. |
Pai, Srikanta |
- |
25 |
| 4. |
M_87 |
- |
24 |
| 5. |
mgritter |
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17 |
| 6. |
mathislife22 |
- |
13 |
| 7. |
lessthanepsilon |
- |
12 |
| 8. |
Azrail |
- |
9 |
| 9. |
Muni |
- |
8 |
| 10. |
JK |
- |
7 |
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 |
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| 1. |
alan |
- |
176 |
| 2. |
denisR |
- |
167 |
| 3. |
idler_ |
- |
104 |
| 4. |
tolstyi |
- |
55 |
| 5. |
vale |
- |
32 |
| 6. |
STARuK |
- |
9 |
| 7. |
Mosk |
- |
2 |
| 8. |
Black, kshor, Mouse,
sergeip, xandr |
- |
0 |
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| Two incense sticks |
Logic puzzles |
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Weight: 1 |
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Liked the puzzle: 100% |
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27.12.2009 |
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| 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. |
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Puzzle statistics "Two incense sticks".
Last updated 71787.2 minutes ago.
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Solved by: 14
Daily average: 0.18
Answers submitted: 14
Viewed by: 27
Fraction solved by: 51.8%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 4
Did not like the puzzle:
0
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| You have 8 coins that appear to be identical, except one (which is
counterfeit) is slightly heavier than the others. What is the
minimal number of weighings on the balance scale that is required to
find the counterfeit coin? |
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Puzzle statistics "8 coins".
Last updated 71787.2 minutes ago.
|
Solved by: 12
Daily average: 0.16
Answers submitted: 13
Viewed by: 26
Fraction solved by: 46.1%
Solved at first attempt: 91.6%
Average discussion length: 1.2
Liked the puzzle: 4
Did not like the puzzle:
0
|
| Two cubes and labels |
Logic puzzles |
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Weight: 2 |
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Liked the puzzle: 100% |
|
19.01.2010 |
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| You have two cubes and sufficiently many labels with digits
0,1,2,..,9. You have to place one label on each face of each cube so
that you can describe any day of the month. The days 1,2 .., 9 should
be described as 01,02,...,09. |
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Puzzle statistics "Two cubes and labels".
Last updated 71787.2 minutes ago.
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Solved by: 5
Daily average: 0.09
Answers submitted: 6
Viewed by: 12
Fraction solved by: 41.6%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 4
Did not like the puzzle:
0
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| Using numbers 1,3,4,6, and basic arithmetic operations (addition,
subtraction, multiplication, and division) and parentheses, obtain and
expression that evaluates to 24. You may use only these numbers and
only these operations. Every number should be used exactly once.
Numbers cannot be concatenated, i.e. you cannot use 13 or 146. |
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Puzzle statistics "Obtain 24".
Last updated 71787.2 minutes ago.
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Solved by: 14
Daily average: 0.18
Answers submitted: 14
Viewed by: 27
Fraction solved by: 51.8%
Solved at first attempt: 92.8%
Average discussion length: 1.1
Liked the puzzle: 5
Did not like the puzzle:
0
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| 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. |
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Puzzle statistics "The fifth number".
Last updated 71787.2 minutes ago.
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Solved by: 10
Daily average: 0.15
Answers submitted: 10
Viewed by: 21
Fraction solved by: 47.6%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 6
Did not like the puzzle:
0
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| 50 coins |
Logic puzzles |
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Weight: 3 |
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Liked the puzzle: 100% |
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27.12.2009 |
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| 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? |
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Puzzle statistics "50 coins".
Last updated 71787.2 minutes ago.
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Solved by: 8
Daily average: 0.1
Answers submitted: 8
Viewed by: 27
Fraction solved by: 29.6%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 3
Did not like the puzzle:
0
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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 truth-teller. 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? |
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Puzzle statistics "A circle of lies".
Last updated 71787.2 minutes ago.
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Solved by: 3
Daily average: 0.05
Answers submitted: 3
Viewed by: 14
Fraction solved by: 21.4%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 2
Did not like the puzzle:
0
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| What is the minimal number of straight cuts required to split a 3x3x3
cube into 27 1x1x1 cubes? Pieces can be rearranged arbitrarily between
the cuts. The answer should justify the minimality. |
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Puzzle statistics "Cutting the cube".
Last updated 71787.2 minutes ago.
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Solved by: 6
Daily average: 0.07
Answers submitted: 7
Viewed by: 27
Fraction solved by: 22.2%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 3
Did not like the puzzle:
0
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| Ladders with missing steps |
Logic puzzles |
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Weight: 5 |
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Liked the puzzle: 100% |
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17.01.2010 |
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| To fix his roof, Megamind needs to climb up a ladder. He has found many ladders to choose from, but unfortunately some of them were missing steps. Megamind cannot climb a ladder if it is missing two or more steps in a row. Originally, all ladders had N steps, marked bottom to top. How many different ladders can Megamind climb? |
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Puzzle statistics "Ladders with missing steps".
Last updated 71787.2 minutes ago.
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Solved by: 3
Daily average: 0.05
Answers submitted: 3
Viewed by: 14
Fraction solved by: 21.4%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 2
Did not like the puzzle:
0
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| A game with sums |
Games puzzles |
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Weight: 5 |
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Liked the puzzle: 100% |
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03.01.2010 |
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| Two players play the following game. An even number of cards are arranged in a row. Each card is marked with a real number. Upon his turn, a player takes a card from either end of the row. Whoever collects the greater sum is a winner. Otherwise, a draw is declared. Which player is guaranteed not to lose? What is his strategy? |
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Puzzle statistics "A game with sums".
Last updated 71787.2 minutes ago.
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Solved by: 3
Daily average: 0.04
Answers submitted: 3
Viewed by: 26
Fraction solved by: 11.5%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 2
Did not like the puzzle:
0
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