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Numbers in a square Patterns and correspondences  Weight: 1 Liked the puzzle: 80% 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  
Defective pixel Algebra, arithmetic  Weight: 1 Liked the puzzle: 100% 03.01.2010

There is true expression on panel. But only one pixel is defective. Which one?

Press for see in full size.
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  
Defective balls Weighing puzzles  Weight: 1 Liked the puzzle: 100% 03.02.2011
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.
Comments:  1 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  
Two villages Knights, Knaves and Jokers  Weight: 2 Liked the puzzle: 100% 27.12.2009
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?
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  
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?
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  
A sequence Patterns and correspondences  Weight: 4 Liked the puzzle: 100% 03.02.2010
1. Continue the sequence a, aa, ba, abaa, aaabba, cabbaa, ... 2. Could symbol "d" eventually appear in this sequence?
Comments:  1 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  
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 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?
Comments:  5 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  
Divide a parallelogram Geometry puzzles  Weight: 5 Liked the puzzle: 100% 02.04.2011
How to divide a parallelogram into 9 isosceles triangles?
Comments:  1 check your solution  



 
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