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Numbers in a square Patterns and correspondences  Weight: 1 Liked the puzzle: 24.12.2011
Place numbers 1,2,.., 9 without repetitions into a 3x3 square so that the sums in all rows, columns, and diagonals are all equal.
Comments:  1 | check your solution  
States and characters Patterns and correspondences  Weight: 1 Liked the puzzle: 100% 26.01.2010
Florida - n, New York - r, Texas - n, Washington - ?
Comments:  1 | check your solution  
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 re-lock to make one long chain?
Comments:  1 | check your solution  
Six glasses Puzzles for children  Weight: 1 Liked the puzzle: 100% 22.01.2011
A row of six glasses is on a table. Three full glasses are followed by three empty glasses. Is it possible to make these glasses alternate: full,empty full, etc by touching only one glass?
Comments:  3 | check your solution  
Obtain 24 Algebra, arithmetic  Weight: 2 Liked the puzzle: 100% 27.12.2009
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.
Comments:  7 | check your solution  
Milk, lemonade, water, and coke Patterns and correspondences  Weight: 2 Liked the puzzle: 100% 27.01.2011
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?
Comments:  4 | check your solution  
Numbers on the fence Patterns and correspondences  Weight: 2 Liked the puzzle: 100% 31.12.2009
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?
Comments:  1 | check your solution  
Weights Weighing puzzles  Weight: 3 Liked the puzzle: 100% 29.01.2010
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.
Comments:  4 | check your solution  
The fifth number Algebra, arithmetic  Weight: 3 Liked the puzzle: 100% 09.01.2010
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.
Comments:  4 | check your solution  
101 coins Weighing puzzles  Weight: 3 Liked the puzzle: 100% 04.01.2010
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?
Comments:  1 | check your solution  
12 coins Weighing puzzles  Weight: 4 Liked the puzzle: 100% 03.02.2010
A Megamind has 12 coins, one of which is counterfeit and weighs differently from the others. He has a balance scale, but no weights. How can the Megamind find the counterfeit coin and determine whether it is lighter or heavier than the standard ones? What is the minimal number of weighings required?
Comments:  1 | check your solution  
A circle of lies Knights, Knaves and Jokers  Weight: 4 Liked the puzzle: 100% 16.01.2010
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?
Comments:  2 | check your solution  
A Megamind in a boat Geometry puzzles  Weight: 4 Liked the puzzle: 100% 27.12.2009
A Megamind is sitting in a boat at the center of a circular lake of radius R. On the lake shore, an evil Goblin awaits. Luckily for the Megamind, the Goblin can only move along the shore. Unfortunately, the Goblin is 4 times as fast as the Megamind in his boat. The Megamind can save himself if he gets to the shore and evades meeting with the Goblin. Can the Megamind save himself? If yes - how?
Comments:  1 | check your solution  
A 52 card trick Logic puzzles  Weight: 5 Liked the puzzle: 100% 26.12.2009
A famous magician takes a standard 52 card deck and gives it to the audience. The spectators choose any 5 cards (they may do it any way they like) and pass these cards to the magician's assistant. The assistant announces 4 of these cards out loud. The magician responds by naming the fifth card. Except for the suit and denomination of each card, the assistant passes no other information to the magician. How does the magician "know" the fifth card?
Comments:  8 | check your solution  
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 upper 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.
Comments:  3 | check your solution  
Rabbits in the store Algebra, arithmetic  Weight: 5 Liked the puzzle: 100% 09.02.2011
In a pet store, the first Megamind bought two plus a half of the remaining rabbits. The second Megamind bought three plus a third of the remaining rabbits. The third Megamind bought four plus a fourth of the remaining rabbits. At some point, one of the Megaminds could not make his purchase. What is the maximal number of satisfied customers (Megaminds)?
Comments:  3 | check your solution  



 
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