Boris Zlotnik (1946) is a USSR, Russian and Spanish chess International Master. He is also a pedagogue and an author.
The first four moves played by White are 1. f3, 2. Kf2, 3. Kg3, 4. Kh4. If White gets mated in the fourth move, what could be the moves played by Black?
The game proceeds as follows:
1. f3 e5 (or e6)
2. Kf2 Qf6
3. Kg3 Qxf3+
4. Kh4 Be7#
An eighty-year-old person was living alone in his house. On a sunny Friday morning, while delivering some letters in the mailbox, the postman felt suspicious and decided to look through the window of the house. That’s when he saw the old man lying dead on the floor in a puddle of blood. When the police arrived, they found three bottles of milk, the Tuesday’s newspaper, and some gifts in front of the house. The lock of the door was broken, and they already suspected a person. Whom and why?
The police suspected the newspaper boy. Since there were 3 bottles of milk, the old man must have been dead for
King Arthur and his eleven honorable knights must sit on a round-table. In how many ways can you arrange the group, if no honorable knight can sit between two older honorable knights?
The answer is 1024 ways, up to rotation around the table. To see this, note that the youngest honorable knight must sit right next to King Arthur – there are two possible places for him. Then, the second-youngest knight must sit right next to this group of two. Once again, there are two possible places for him. Continuing like this, we see that for all honorable knights, except for the oldest one, there are two possible spots on the table. Multiplying two to the power of ten out, we get 1024.
Puzzil Primus was born on the 314th day of year 20B.C. and died on the 271st day of year 20A.D. How old was he when he died?
Puzzil Primus was 38 years old. This is because day 314 comes after day 271, and also there is no year 0 in the calendar.
A beetle is located in the center of a square carpet. The edges of the carpet are colored in red, green, blue, and yellow. Four spiders of the same colors are on the carpet’s corners. Each spider can only move on the edge with its matching color. Can the beetle escape the carpet and flee without encountering the spiders if it is 1.5 times slower than them?
No, the spiders will always be able to contain the beetle within the carpet. We draw two perpendicular lines passing through the beetle which are parallel to the diagonals of the square. The spiders’ strategy is to follow the four points where these lines intersect with the boundary of the square. When a spider’s corresponding intersection point moves to an edge of a different color, the spider waits in the corner. In order to accomplish this strategy, the speeds of the spiders need to be at least √2~1.4 times higher than the speed of the beetle.
Bob and Jane are taking turns, placing knights and coins respectively on a chessboard. If Bob is allowed to place a knight only on an empty square which is not attacked by another knight, how many pieces at most can he place before running out of moves? Assume that Jane starts second and plays optimally, trying to prevent Bob from placing knights on the board.
Bob can place at most 16 knights. One way to do this is to keep placing knights only on the 32 white squares. In order to see that Jane can prevent Bob from placing more than 16 knights, split the board in four 4×4 grids. Then, group the squares in each grid in pairs, as shown on the image below. If Bob places a knight on any square, then Jane will place a coin on its paired square. This way Bob can place at most one knight on each of the four red squares, one knight on each of the four green squares, one knight on each of the four brown squares, and one knight on each of the four blue squares. Therefore, he can not place more than 64/4 = 16 knights on the board.
Can you recognize which famous movies are depicted by these images?
There are three light bulbs in your attic. All of them are turned off and their switches are installed downstairs. You can play with the switches as much as you want and after that
You turn the first switch on, then wait for 30 minutes and turn the second switch on. After that go upstairs and examine the bulbs. The one which is turned off corresponds to the third switch. The one which is turned on and is still cold corresponds to the second switch. The one which is turned on and is hot corresponds to the first switch.
With 12 matches you can easily create a shape with area 9 and a shape with area 5, as shown on the picture below. Can you rearrange the 12 matchsticks, so that they encompass an area of 4?
Remark: You should have only one resulting shape and no matches should be unused.
First, create a Pythagorean triangle with sides 3, 4, 5, and area 6. Then simply flip its right angle inwards, so that the area decreases by 2.
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