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Challenge 49

Balls in the box Difficulty level: Clodoémerson has several balls 10 cm in diameter. Putting one at a time, how many balls can he put in an empty box, cubic, 1 meter in side? Challenge 48 Share the apples among the children Challenge index Next >> Challenge 50 Divide the wine among the drunks
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Challenge 41

Solve the equation Difficulty level: The solution to equation y 2 - log y = 0.001 is… Challenge 40 Who is the big brother? Challenge Index Next >> Challenge 42 Row of Bottles
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Challenge 7

Where is it? Difficulty level: Consider the numbers obtained from the number 12345, making all the permutations of their numbers. Putting these numbers in ascending order, what is the place occupied by the number 43521? Challenge 6 What is the number? Challenge Index Next >> Challenge 8 On the Tic Tac Toe Board
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Challenge 56

Flock of Mallards Difficulty Level: Two hunters went out to slaughter mallards on a hunting trip by a large lake. Here comes a band of teals, commanded by a leader and guided by a battling teal. Upon sighting the hunters, the scouting morocco immediately alters the pack's route, taking its mates to safety.
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Challenge 191

The boy, the sneakers and the whistles Difficulty level: Look at the four equations below, from which you can identify that each figure (boy, sneakers and whistles) has a different value. Your challenge is to find out what the result of the last equation is. Pay close attention as the details make the difference!
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Challenge 60

The Chocolate Company Difficulty Level: The cost price of a chocolate is $ 0.20 each. The chocolate factory calculates that if they sell each chocolate for real 'x', consumers will buy 10- x chocolates a day. What is the selling price of chocolate that maximizes the business owner's profit?
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Challenge 64

How much is $ 10.00 times $ 10.00? Difficulty level: 10 times 10 equals 100. How much is $ 10.00 times $ 10.00 ??? Challenge 63 Octagonarian and His Great-grandson Challenge Index Next >> Challenge 65 How Many Men Need to Leave the Room?
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Challenge 4

How many triangles? Difficulty Level: There are N distinct triangles with the vertices at the points of the figure. What is the value of N? Challenge 3 Age Ratio Challenge Index Next >> Challenge 5 How Much Money?
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Challenge 77

The two watches Difficulty level: A man has two watches. One does not walk and the other is an hour late. Which one will most often show the right time? Challenge 76 Great-grandfather's age Challenge index Next >> Challenge 78 Cooking the Egg
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Challenge 73

Number 6 with 3 equal digits Difficulty level: Find 9 ways to represent number 6 with 3 equal digits by placing the signs between them. Any mathematical sign can be used as long as no more numbers appear. Example: 2 + 2 + 2 = 6 (find the other 8) Challenge 72 Number 2 to 9 Challenge Index Next >> Challenge 74 Two Parents and Two Children
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Challenge 81

Surprise at the restaurant Difficulty level: Three friends went to eat at a restaurant and in the end the bill gave $ 30.00. They did the following: each gave $ 10.00. The waiter took the money to the cashier, and the restaurant owner said, "These three are old customers of the restaurant, so I'll give them $ 5 back." And handed the waiter five $ 1 coins.
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Challenge Response 104

Clodovando's father and grandfather If x represents the last two digits of the year the father was born, then x + x = 38, because the statement says that the last two digits were their ages in 19 38. Solving the equation: x + x = 38 2x = 38 x = 19 Thus, the father was born in 19 19 and was 19 years old in 1938. If the father was born in 1919, the grandfather could only have been born in the previous century (18XX).
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Challenge 86

The Big Family Difficulty Level: In a family there are three mothers, three daughters, two grandparents, two granddaughters, a great-grandmother, and a great-granddaughter. How many people make up this family? Challenge 85 Saint Anthony miracle worker Challenge index Next >> Challenge 87 How old was Claudiomiro?
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Challenge 83

Seu Manoel's Account Difficulty Level: A young man came into Seu Manoel's bar and ordered a sip, a bag of chips, a soda and a pack of cigarettes. Manoel takes the pencil from behind his ear, writes the price on a piece of paper and gives it to the boy, who is furious: - You have multiplied the price of the things I bought!
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Challenge Response 119

Beatriz's early clock We know that every hour the minute hand rotates the clock 360º, ie 6º per minute. As for the hour hand, it rotates 30º (which is the angle between two hour marks) per hour. That is, 1st every 2 minutes, or half a degree per minute.
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Challenge Response 122

How much should the jeweler pay? According to the combination of the two, the jeweler would have to pay R $ 20,00 for the lodging if he sold the jewels for R $ 100,00 and would have to pay R $ 35,00 if he sold them for R $ 200,00. We have: Sale price Accommodation cost 200 35 100 20 The difference of R $ 100,00 in the sale price corresponds to a difference of R $ 15,00 in the price of the accommodation.
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Challenge 96

Robervaldo's ducks Difficulty level: Robervaldo raised ducks. One day a man came to his farm and offered him $ 200 per duck and $ 50 per egg. In total Robervaldo had 12 ducks. However, 2 of them were pet friendly, so he decided not to sell them. The other ducks were sold.
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Challenge 98

Vanderlei Cordeiro and the Marathon Difficulty Level: In a marathon, Brazilian Vanderlei Cordeiro de Lima had already completed 2/5 of the race's full course, when a former Irish priest stormed the track and held the athlete. Vanderlei, who was 40km from halfway, was saved by the Greek citizen Polyvios Kossivas and continued in the race, winning the bronze medal.
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Challenge 92

Reducing Inmates 'Penalties Difficulty Level: A certain authority visited a prison and halved prisoners' penalties. That is: prisoners who were supposed to be 10 years old, were now 5 years old; who was to fulfill 2 became only 1, and so on. What did he do to resolve the issue of prisoners who were sentenced to life imprisonment?
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