Math practice for 13 year olds - page 51 of 424
Number of problems found: 8477
- Left-handed
There are 100 people in a room, 99% of whom are left-handed. How many left-handed people must leave the room to reduce this proportion to 98%? - Peter 27
Peter earned twice as much as Jano from his part-time job. Jano earned €50 less than Peter. How much did each of them earn? - Irregular
Calculate the area and perimeter of a garden created from a rectangular plot measuring 10 m by 20 m after cutting off one corner measuring 6 m by 7 m. The removed rectangular section has sides parallel to those of the main plot. Did the perimeter of the r - Thinking unknown n
I am thinking of a number. If I subtract 14 from it and multiply the result by 6, I get 210. What is the number? - Spiral - iron
An electric iron is connected to a 230 V power source. Its heating element has an electrical resistance of 100 ohms. Calculate the power of the iron and the electric current flowing through the element. - Tank 28
A tank fills in 120 hours. When drained for irrigation, it empties in 10 days. How long will it take to fill if filling and draining occur simultaneously? - Oranges and apples
Mr. Novák bought 5 times more oranges than apples. One orange cost 8 CZK and one apple cost 12 CZK. He paid 156 CZK in total. How many oranges and apples did he buy? - Asphalt
A tennis court can have a grass, asphalt, or clay surface. A singles court is 23.78 m long and 8.23 m wide. For doubles, a strip 1.37 m wide is added on both longer sides. By how many m² is a doubles tennis court larger than a singles court? - Railing 3
A railing in a museum is filled with 18 glass panels in the shape of parallelograms with a side length of 40 cm and a corresponding height of 65 cm. How many m² of glass were needed to produce these panels? - Consolidation expensiveness
Calculate how much the same shopping of 100 EUR will cost in 2025, if in 2024 VAT is 20% and in 2025 it will be as much as 23%. Assume that all goods in the shopping are charged with the same, basic VAT rate. PS. VAT was temporarily raised from 19% to 20% - Expanding A problem has spread here — money printing. The ECB claims it aims to maintain a price level with 2% inflation. However, for the last three years in a row, annual inflation has been 6%, 7%, and 9%.
- Divisible PIN
Mark's mother helped him with his shopping. She wanted to pay by card when collecting the goods in person, but she was not sure what her PIN was. Could her PIN be a number divisible by six? - Triangles - combinations
How many different triangles with sides of whole centimetres have a perimeter of 12 cm? - Employees in a company
A company with 326 employees decided to build a parking lot for employees. In the parking lot design there are 84 parking spaces for cars. Each parking space for cars can be replaced with 3 parking spaces for motorcycles. Calculate the total number of veh - Determine 23
Determine in cm² the area of rectangle ABCD, whose longer side is a = 20 cm and whose diagonal is 10 cm longer than its shorter side. - Wall and ladder
A ladder leans against a wall, reaching a height of 6.5 m. How long is the ladder if it makes an angle of 60° with the horizontal floor? - Production
A company's production in February was 15% greater than in January and 25% less than in March. By what percentage was production in March higher than in January? - Isosceles gable
The gable of a cottage roof is in the shape of an isosceles triangle with a base of 8 m and legs of 10 m. How high is the gable? - Diagonal 2
What is the area in square metres of a rectangular garden whose diagonal is 50 m long and whose width is 27 m? Round the result to the nearest whole number. - Acceleration of a car
What was the initial speed of a car that, after accelerating at 2 m/s², reached a speed of 30 m/s in 10 seconds?
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