 |
| 1. |
markr |
- |
100 |
| 2. |
monkeyspike |
- |
28 |
| 3. |
Pai, Srikanta |
- |
25 |
| 4. |
M_87 |
- |
24 |
| 5. |
mgritter |
- |
17 |
| 6. |
mathislife22 |
- |
13 |
| 7. |
lessthanepsilon |
- |
12 |
| 8. |
Azrail |
- |
9 |
| 9. |
Muni |
- |
8 |
| 10. |
JK |
- |
7 |
|
 |
 |
 |
| 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 |
|
 |
 |
|
| 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 67129.7 minutes ago.
|
Solved by: 14
Daily average: 0.19
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
|
|
|
| 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? |
 |
|
|
Puzzle statistics "8 coins".
Last updated 67129.7 minutes ago.
|
Solved by: 12
Daily average: 0.17
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
|
|
|
| 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. |
 |
|
|
Puzzle statistics "Obtain 24".
Last updated 67129.7 minutes ago.
|
Solved by: 14
Daily average: 0.19
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
|
|
|
| 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 67129.7 minutes ago.
|
Solved by: 6
Daily average: 0.08
Answers submitted: 7
Viewed by: 27
Fraction solved by: 22.2%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 2
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 67129.7 minutes ago.
|
Solved by: 10
Daily average: 0.16
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
|
|
|
| Among 101 coins, exactly 50 are counterfeit. A counterfeit coins
weighs one gram more or gram less than the real coin (counterfeit
coins may weigh differently). You have a balance scale that shows the
exact weight differential between the two cups. How can you
determine whether a given coin from this set is counterfeit using the
scale only once? |
 |
|
|
Puzzle statistics "101 coins".
Last updated 67129.7 minutes ago.
|
Solved by: 6
Daily average: 0.09
Answers submitted: 6
Viewed by: 24
Fraction solved by: 25%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 2
Did not like the puzzle:
0
|
| The mouse hunt |
Games puzzles |
 |
Weight: 4 |
 |
Liked the puzzle: 100% |
 |
11.01.2010 |
|
| A smart cat named Leopold is hunting a mouse. A mouse is hiding in one
of five holes arranged in a row. Leopold can reach into one of the
holes and try to catch the mouse. If he is not successful, the scared
mouse runs into a right/left neighboring hole. Is it guaranteed that
Leopold will catch the mouse? If so, what should he do? |
 |
|
|
Puzzle statistics "The mouse hunt".
Last updated 67129.7 minutes ago.
|
Solved by: 3
Daily average: 0.05
Answers submitted: 4
Viewed by: 20
Fraction solved by: 15%
Solved at first attempt: 66.6%
Average discussion length: 1.3
Liked the puzzle: 2
Did not like the puzzle:
0
|
|
|
| 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? |
 |
|
|
Puzzle statistics "A circle of lies".
Last updated 67129.7 minutes ago.
|
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
|
| A game with sums |
Games puzzles |
 |
Weight: 5 |
 |
Liked the puzzle: 100% |
 |
03.01.2010 |
|
| 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? |
 |
|
|
Puzzle statistics "A game with sums".
Last updated 67129.7 minutes ago.
|
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
|
| A poisoned chocolate bar |
Games puzzles |
 |
Weight: 5 |
 |
Liked the puzzle: 100% |
 |
26.12.2009 |
|
| A chocolate bar consists of NxM (at least two) square pieces arranged in a rectangle. The square in the lower left corner is poisoned. Two players break off the squares from the bar and eat them. If a player chooses a certain square, he must also take all of the remaining squares that have row/column numbers not less than the chosen one. A player forced to take the poisoned square loses. Prove that the first player to make a move has a winning strategy. |
 |
|
|
Puzzle statistics "A poisoned chocolate bar".
Last updated 67129.7 minutes ago.
|
Solved by: 5
Daily average: 0.06
Answers submitted: 5
Viewed by: 28
Fraction solved by: 17.8%
Solved at first attempt: 100%
Average discussion length: 1.0
Liked the puzzle: 2
Did not like the puzzle:
0
|
|
|