Reason - practice for 13 year olds - page 9 of 41
Number of problems found: 809
- Pigs
A buyer said, "I want to buy 100 pigs for 100 denarii. An adult pig costs ten denarii, a sow five denarii, and two little piglets are worth one denarius. " How many pigs, cows, and piglets could he buy for exactly 100 denarii? - Arithmetic 40671
The number 20 is the arithmetic mean of the eight numbers. Determine their sum. - Average weight
Mom bought six apples with an average weight of 130 g - If she took one apple out of the bag, the average weight of the remaining apples changed to 140 g. What was the weight of the removed apple? - Together
The three friends divided the balls in a ratio of 6:5:4. Some two got 126 balls. How many balls were there together?
- Karolína
Carolina chose five bodies from the kit - white, blue, and gray cubes, a blue cylinder, and a white triangular prism. How many different roof towers can be built one by one if all the blue bodies (cube and cylinder) are not placed on top? - Three-digit 38371
How many odd three-digit numbers can you make of the five cards with the numbers 1, 2, 3, 5, and 6? - Two ports
Between the ports of Mumraj and Zmatek, two ships commute along the same route. They spend negligible time in ports, turn around immediately, and continue sailing. At the same time, a blue ship departs from the port of Mumraj, and a green ship departs fro - Coloured numbers
Mussel wrote four different natural numbers with colored markers: red, blue, green, and yellow. When the red number divides by blue, it gets the green number as an incomplete proportion, and yellow represents the remainder after this division. When it div - 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
- Ground level
The ground-level temperature in Helsinki is 20°C lower than in London. The temperature in a basement flat in Helsinki is 5°C below the temperature at ground level. If it is -29°c in the basement, what is the temperature in London? - Distinguished 37083
Three circles of the same size are drawn on the playing field. Arrange the 16 pins so that there are 9 pins in each circle. Find at least eight significantly different layouts, i.e. J. such layouts in which pins or circles are not distinguished. - Barborka 36393
Adela and Barbora have a total of 34 candies. If Barbora gives Adela 2 candies, they will have the same. How many candies does Adela have, and how many Barbora? - Triangle 35881
The sum of the lengths of the two sides b + c = 12 cm Beta angle = 68 Gamma angle = 42 draw triangle ABC - Round table
Eight people are sitting at a round table. In how many ways can they be seated around the table?
- 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 - Following 34291
The following holds for two non-empty sets, A and B: A ∪ B has 16 elements, A ∩ B has 11 elements, and the set A - B is empty. How many elements does set B-A to have? - One dice
Calculate the probability of one dice roll with the numbers 1, 2, 3, 4, 5, and 6 on the walls. Write the results in a notebook in the shape of a fraction in the basic form: 2/3. a The number 1 falls on the cube. b, The number 5 falls on the cube. c, An ev - Three dice
The player throwing the three dice asked G. Galilei: "Should I bet on the sum of 11 or the sum of 12?" What did Galilei answer him? Hint: write down all three triples of numbers that can be thrown, have a total of 11, have a total of 12, and compare proba
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