Puzzles Kids +

Puzzles & Illusions

Easy Medium Hard

by Gianni A. Sarcone and Marie-Jo Waeber

Puzzle No 1.

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Watering can problem Marc’s sister is a garden hobbyist. One day, she went to a garden center to buy a watering can. The sales-clerk suggests 3 possible variants having however the same base surface: watering can A, which costs 3.00 dollars; B, which costs 3.50 dollars; and C, that costs 2.00 dollars. What is in your opinion the most convenient if your choice is imposed by the capacity?

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Keyword: capacity = the maximum amount that something can contain.

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Watering can problem

The watering can A because it is cheaper than B and can contain the largest capacity compared to the other two sets. The amount of water that can be kept within each watering can is determined by the HEIGHT of the drum and, above all, of the spout.

The water level cannot rise above the spout opening since any extra water would merely spill out from the spout. A simple visual estimate would conclude that the spout of watering can A is higher to that of watering can B. Distributed by Knight Features www.knightfeatures.com

Puzzle No 2.

Tricolor Look at the tricolor banner of the royal trumpeter. Can you say how many banners can be made with two available colors (red and/or green) plus white if two adjacent strips must NOT be of the same color? On your opinion: 4, 6, 12 or 24?

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Tricolor Exactly 12! Each of the 3 initial color strips of the banner can have 2 x 2 different possibilities.

For instance: if the first strip is red, the second strip must be green or white (2 colors), but if the second strip is green, then the third strip must be red or white (also 2 colors). That makes 3 x 2 x 2 = 12 different colored banners.

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Puzzle No 3.

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Impossible chain?

A chain of 15 linked snap-hooks can be separated into five smaller parts by opening just four single snaphooks (fig. B). Is it possible to link together the five chain portions (fig.

C) to form the initial chain again (fig. A) by opening only three single snap-hooks?

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Impossible chain Open 3 snap-hooks of 1 chain portion (3 operations).

With these link the other 4 chain portions together.

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Puzzle No 4.

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Lateral thinking

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Zen Thoughts An apprentice drew a line on a paper and asked a Zen monk: “Mater, is it possible to make the painted line shorter without touching any part of it?”.

The Zen monk kept silence, then he showed the apprentice how to do it...

What did he exactly do to solve the puzzle?

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Keyword: Zen is a discipline and philosophy which emphasizes the value of meditation and intuition.

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Zen Thoughts He drew a larger line next to the first one, the first line was then definitively shorter...

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Puzzle No 5.

Magic word Using the Scrabble letters below try to build a word following this instruction: It is a word that contains itself seven times.

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Language

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Magic word 1

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L E T T E R S 1

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the word “letters” contains 7 ‘letters’. Such puzzles are called self-referential puzzles. A word or a sentence is said to be self-referential when it refers to itself, like: - This statement finishes right here, - This sentence contains thirty-eight letters, or - This sentence was in the past tense...

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Puzzle No 6.

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Dinner club Dexter, the Maître d’Hôtel at restaurant ‘Pesto & Pasta’, welcomes a photography club for a dinner. For the occasion, he prepared 8 tables for each couple of the club (see fig. 1). A number has previously been attributed to each couple, from 1 to 8. The problem is that Dexter discovered that there is some dislike between couples having neighboring numbers! So, he must ensure that each couple of the club will not be in direct contact, laterally or diagonally, with another couple with a preceding or following number (see examples of fig. 2). How will he accomplish his task?

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fig. 1

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Neighboring numbers cannot be in direct contact!

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fig. 2

Dinner Club See solution opposite. By rotation and symmetry, we can find 3 other solutions. However, 8 and 1 will always occupy the central tables of the table arrangement.

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Puzzle No 7.

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5 x 5 vowels Here is a puzzle that will challenge your memory and enrich your vocabulary! Think of 5 words related to the world of mathematics and geometry having all the five vowels a, e, i, o, u ONCE...

Language

5 x 5 vowels Here is a list of possible words related to mathematics containing all 5 vowels once:

Numeration, incomputable, equation, duodecimal, volumetrically, mensuration, permutation...

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Connection dilemma We’ve laid on water, internet connection and electricity from the utility suppliers X, Y, Z to each of the 3 houses A, B and C without any pipe crossing another. Take a pencil and check if the work has been done properly!

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fig. 1

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Connection dilemma

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Puzzle No 8.

If we differentiate with colors the relative connections which start from the utility suppliers X, Y and Z, we can see that some houses (A and C) are connected twice to the same utility supplier (fig. 1)... In fact, it is NOT POSSIBLE to connect the buildings X, Y, Z to each of the 3 houses without intersecting a pipe! As shown in fig. 2, two utility suppliers will always ENCLOSE one of the house, making it impossible for the third utility supplier to connect the house without intersecting a pipe.

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Puzzle No 9. Šwww.archimedes-lab.org

Red & golden apples A greengrocer received 30 red apples and 30 golden apples from his wholesaler. The recommended prices were one dollar for 2 red apples and one dollar for 3 golden apples. To avoid color disparity he decided to sell a conflation of 5 apples for two dollars. He thought that there is no difference between selling 5 apples for two dollars, and selling 3 for one dollar and 2 for one. Curiously enough, he sold all the fruits and earned 24 dollars - one dollar less than expected!

Can you explain why?

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Red & golden apples As you can see from the image, the red and golden apples together make ten bunches of five apples you can reasonably sell for two dollars. The last two bunches are made only with red apples that cost effectively much more than two dollars the price at which they have been sold! Therefore the loss of one dollar depends on the price difference of these last ten red apples.

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Round-trip Joe had just arrived at school when he realized that he forgot his math textbook at home. So he headed home on his skateboard (his house is downhill from the school) at an average speed of 6 km per hour. Once at home, he took the book and walk back to school uphill at an average speed of 4 km per hour.

Can you guess what was the total average speed of his round-trip?

A. SCHOOL

6 km/hour

4 km/hour

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Round-trip This is a tricky puzzle. Most people answer 5 km/hour. However, the actual answer is 4.8 km/hour instead! Why? Because you have to consider the TIME spent to cover these distances.

Let us say that the distance covered from A to B is 6 km/hour x 10 minutes or 6 km/hour x 1/6 hour = 1 km, then to travel from B to A takes 1 km.

At 4 km/hour it takes 1/4 hour. If we divide the distances 2 x 1 km by the time spent to cover them (1/6 hour + 1/4 hour = 5/12 hour), we obtain an average of 4.8 km/hour (2 x 1 km : 5/12 hour = 4.8). Meaning the total amount of time for the trip is the same as if you traveled the entire trip at 4.8 kilometer per hour.

In mathematics, such an average is called “harmonic mean” and it is used in electronics to calculate the mean resistance of two or more resistors connected in parallel.

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Puzzle No 10.

Puzzle No 11.

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Is the glass half-empty or half full?

Albert, while enjoying a pint of very good beer, wonders if there is a simple way to settle if his beer glass is half-empty (or half full) without using stick, string, or implement of any kind for measuring. Hic! Sorry...

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Is the glass half-empty or half full?

All that is necessary is to tilt the glass as shown in figures 1 to 3, and if the edge of the surface of the beer exactly touches the lip of the beer glass at the same time that it touches the edge of its bottom, it will be just half full (or half-empty, see fig. 2). This method applies to all SYMMETRICALLY constructed vessels.

fig 1.

fig 2.

fig 3.

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Puzzle No 12.

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Dutch puzzle Two canal boats meet two other canal boats coming from the opposite direction near a larger area of the canal. The larger area allows the parking of just one canal boat. Then, how should the captains Dick, Jan, Matthijs and Klaas maneuver their boat in order to continue their run the most rapidly as possible?

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Dutch puzzle The puzzle can be solved in 7 steps:

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Puzzle No 13.

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Visuo-spatial skills

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The amazing 3-piece Tangram Reproduce the diagram opposite onto a thin cardboard sheet, then cut out the 3 pieces and try to form with them the 3 shapes shown below. It seems very easy, but it’s not!

To form the shapes the pieces must touch but not overlap, and may be rotated or flipped.

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The amazing 3-piece Tangram

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