Mathematical Olympiad - practice problems - page 3 of 9
Direction: Solve each problem carefully and show your solution in each item.Number of problems found: 176
- Coloured numbers
Mussel wrote four different natural numbers with colored markers: red, blue, green, and yellow. When the red number is divided by blue, it gets the green number is an incomplete proportion, and yellow represents the remainder after this division. When it
- Squirrels
The squirrels discovered a bush with hazelnuts. The first squirrel plucked one nut, the second squirrel two nuts, and the third squirrel three nuts. Each new squirrel always tore one nut more than the previous squirrel. When they plucked all the nuts from
- Shepherd
Kuba makes a deal with a shepherd to take care of his sheep. Shepherd said to Kuba that he would receive twenty gold coins and one sheep after a year of service. But Kuba resigned just after the seventh month of service. But the shepherd rewarded him and
- All pairs
Find all pairs (m, n) of natural numbers for which is true: m s (n) = n s (m) = 70, where s(a) denotes the digit sum of the natural number a.
- Dance ensembles
Four dance ensembles were dancing at the festival. None had less than ten and more than 20 members. All dancers from some of the two ensembles were represented in each dance. First, 31 participants were on the stage, then 32, 34, 35, 37, and 38. How many
- Z6–I–5 MO 2019
The shape in the picture was created by cutting a small cross out of a large cross. Each of these crosses can be composed of five identical squares, with the sides of the small squares being half the sides of the large squares. The area of the gray shap
- Z6 – I – 6 MO 2019
Mother studied multi-digit numbers in which odd and even digits regularly alternate. Those that start with an odd digit she called comical and those that start with an even digit she called cheerful. (E.g. The number 32387 is comical, the number 4529 is c
- Construct 11511
Construct the diamond ABCD so that its diagonal BD is 8 cm and the distance of apex B from the line AD is 5 cm. Specify all options
- Z8–I–5 MO 2019
For eight different points as shown in the figure, points C, D, and E lie on a line parallel to line AB, F is the midpoint of line AD, G is the midpoint of line AC, and H is the intersection of lines AC and BE. The area of triangle BCG is 12 cm² and the
- Four-digit 10261
Roman likes magic and math. Last time he conjured three- or four-digit numbers like this: • created two new numbers from the given number by dividing it between digits in the place of hundreds and tens (e.g., from the number 581, he would get 5 and 81), •
- Subtract 10001
For five whole numbers, if we add one to the first, multiply the second by the second, subtract three from the third, multiply the fourth by four, and divide the fifth by five, we get the same result each time. Find all five of the numbers that add up to
- The king
The king divided ducats among his sons. He gave the eldest son a certain number of ducats, gave the younger one ducat less, gave the other one ducat less, and proceeded to the youngest. Then he returned to his eldest son, gave him one ducat less than a wh
- Twos
Vojta started writing the number this year, 2019202020192020, into the workbook. And so he kept going. When he wrote 2020 digits, he no longer enjoyed it. How many twos did he write?
- Circumference 9811
Kristýna chose a certain odd natural number divisible by three. Jakub and David then examined triangles with a circumference in millimeters equal to the number selected by Kristýna and whose sides have lengths in millimeters expressed by different integer
- Between two bus stops
Wanda lives between two bus stops at three-eighths of their distance. He started the house today and found that he would have arrived at the bus stop if he had run to one or the other. The average bus speed is 60 km/h. What is Wanda's average running spee
- Complaining 9611
Ondra, Mathias, and Kuba are returning from collecting nuts. They have a total of 120. Mathias complains that Ondra has the most, as always. The father orders Ondra to sprinkle it on his Mathias so that the number of nuts doubles. Now Cuba is complaining
- Three-digit 9601
Majka researched multi-digit numbers, in which odd and even numbers alternate regularly. Those who start with an odd number are called comics, and those who start with an even number are called cheerful. (For, number 32387 is comic, and number 4529 is hil
- Matemakak 9432
The cookbook by Matěj Matemakak says: The greatest common divisor of flour weight and sugar weight is 15, the greatest common divisor of sugar weight and lemon peel weight is 6, the product of sugar weight and lemon peel weight is 1800, and the smallest c
- Sufficient 9391
In Kocourkov, they use coins with only two values expressed in Kocourkov crowns by positive integers. With a sufficient number of such coins, it is possible to pay any integer amount greater than 53 cats’ crowns accurately and without return. However, we
- Richard's numbers Z8-I-2 2019
Richard was playing with two five-digit numbers. Each consisted of different digits, which in one were all odd and in the other all even. After a while, he found that the sum of these two numbers starts with the double digit 11 and ends with the number 1
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