It is known that “copper” coins that are worth 1, 2, 3, 5 pence weigh 1, 2, 3, 5 g respectively. Among the four “copper” coins (one for each denomination), there is one defective coin, differing in weight from the normal ones. How can the defective coin be determined using scales without weights?
How can we divide 24 kg of nails into two parts of 9 kg and 15 kg with the help of scales without weights?
Five first-graders stood in line and held 37 flags. Everyone to the right of Harley has 14 flags, to the right of Dennis – 32 flags, to the right of Vera – 20 flags and to the right of Maxim – 8 flags. How many flags does Sasha have?
It is known that in January there are four Fridays and four Mondays. What day of the week is January 1st?
A class contains 38 pupils. Prove that within the class there will be at least 4 pupils born in the same month.
How, without any means of measurement, can you measure a length of 50 cm from a shoelace, whose length is \(2/3\) meters?
The Olympic gold-medalist Greyson, the silver-medalist Blackburn and bronze-medalist Reddick met in the club before training. “Pay attention,” remarked the black-haired one, “one of us is grey-haired, the other is red-haired, the third is black-haired. But none of us have the same colour hair as in our surnames. Funny, is not it?”. “You’re right,” the gold-medalist confirmed. What color is the hair of the silver-medalist?
On the street, four girls are talking in a circle: Anna, Kate, Jane and Nina. The girl in the green dress (not Anna and not Kate) stands between the girl in the blue dress and Nina. The girl in the white dress stands between the girl in the pink dress and Kate. What color dress was each girl wearing?
Find a two-digit number that is 5 times the sum of its digits.
Decipher the puzzle shown in the picture. Same letters correspond to same numbers, different letters to different numbers.