One three-digit number consists of different digits that are in ascending order, and in its name all words begin with the same letter. The other three-digit number, on the contrary, consists of identical digits, but in its name all words begin with different letters. What are these numbers?
There are five chain links with 3 rings in each. What is the smallest number of rings that need to be unhooked and hooked together to connect these links into one chain?
During a chess tournament, some of the players played an odd number of games. Prove that the number of such players is even.
There are scales without weights and 3 identical in appearance coins, one of which is fake: it is lighter than the real ones (the real coins are of the same weight). How many weightings are needed to determine the counterfeit coin? Solve the same problem in the cases where there are 4 coins and 9 coins.
We have scales without weights and 3 identical in appearance coins. One of the coins is fake, and it is not known whether it is lighter or heavier than the real coins (note that all real coins are of the same weight). How many weighings are needed to determine the counterfeit coin? Solve the same problem in the cases where there are 4 coins and 9 coins.
Decipher the following rebus. Despite the fact that only two figures are known here, and all the others are replaced by asterisks, the question can be restored.
48 blacksmiths must shoe 60 horses. Each blacksmith spends 5 minutes on one horseshoe. What is the shortest time they should spend on the work? (Note that a horse can not stand on two legs.)
In Wonderland, an investigation was conducted into the case of a stolen soup. At the trial, the White Rabbit said that the soup was stolen by the Mad Hatter. The Cheshire Cat and the Mad Hatter also testified, but what they said, no one remembered, and the record was washed away by Alice’s tears. During the court session, it became clear that only one of the defendants had stolen the soup and that only he had given a truthful testimony. So, who stole the soup?
Do you think that among the four consecutive natural numbers there will be at least one that is divisible a) by 2? b) by 3? c) by 4? d) by 5?
The stepmother, leaving for the ball, gave Cinderella a sack which contained a mixture of poppy and millet, and ordered them to be sorted. When Cinderella was leaving for the ball, she left three sacks: one contained millet, the other contained poppy, and in the third – a mixture that had not yet been sorted. In order not to confuse the sacks, Cinderella attached a label to each of them that said: “Poppy seed”, “Millet” and “Mixture”. The stepmother returned from the ball first and deliberately swapped all of the labels in such a way that on each sack there was an incorrect inscription. The fairy godmother managed to warn Cinderella that now none of the labels on the sacks were correct. Then Cinderella took out only one single grain from one sack and, looking at it, immediately guessed what was in each sack. How did she do this?