Math practice for 13 year olds - page 69 of 435
Number of problems found: 8682
- We randomly
We randomly select a three-digit number. What is the probability that the number 8 occurs at most once in its notation? - Competition 81952
All three team members took turns fulfilling the competition task without delay. The first member used up 30% of the total competition time. The second needed 10 minutes more than the first, and only 10 minutes remained for the third. What % of the total - Calculate 81950
The tangent of the angle formed by the adjacent sides of the triangle ABC (side a=29 m, b = 40 m) equals 1.05. Calculate the area of that triangle. - Inscribed cube
A cube is inscribed in a sphere with a radius of 27 cm. Calculate its volume and surface area. - Applies 81948
From a rented house worth 1.25 million CZK, the owner will receive an annual rent of 6.5% of the house price. 20% tax applies to the rent. How much CZK will the owner have from the rent per year? - Small density cube
Calculate the mass of a cube with an edge of 15 cm made of oak wood with a density of ρ = 800 kg/m³. - Increased 81943
The mobile was increased by a quarter of the original price and then again by a quarter of the new price. How much did the mobile cost if its final price was 125 euros?
- Consumption 81941
The car consumes up to 16 l in the city, but on a longer trip, the consumption drops to 10 l? 500 km per month in the city and 1650 km outside the city. What is the consumption of a car per 100 km? - Calculate 81939
The block surface is 5,632 m². The lengths of the edges are in the ratio 1: 2 : 3. Calculate the volume of the cuboid. - Increased 81938
We increased the side of the square by 12% from the original 15cm. For a, what was the perimeter and area of the new square? By what percent did the perimeter and area increase? - Cantilevers 81937
Calculate a prism's volume and surface area with a base of a right triangle with cantilevers of length 40 and 43 cm. The height of the prism is 60 cm. - Calculate 81936 The volume of the block is 7,500 dm³. The lengths of the edges are in the ratio 3: 4: 5. Calculate the surface area of the cuboid.
- Calculate 81935 The volume of the cuboid is 960 cm³. The lengths of the edges are in the ratio 1 : 3: 5. Calculate the surface area of the cuboid.
- Cube-shaped 81931
A ball with a diameter of 10 cm is in a cube-shaped box with an edge of 10 cm. What percentage of the box does the ball fill? - Distribution 81926
There are 28 pupils in the class. Twenty-seven of them wrote the control paper in mathematics. Four students had a one, 8 had a two, 12 students had a three, and 3 had a four. Express this distribution as a percentage.
- Subtracting 81925
Three horses will eat 36 kg of oats in two days. How many kilograms do 5 horses need for 4 days? Help yourself by adding or subtracting. - Foresters 81919
Foresters planted 2,440 saplings in three days. On the second day, they planted 20% more saplings than on the first day, and on the third day, 15% less than on the first day. How many saplings did the foresters plant each day? - Percentage 81914
The carpenter worked on a rotary cylinder with a base radius of 2.5 dm and a height of 2 dm. He reduced the radius by 1 cm by uniform grinding, and the height of the cylinder was preserved. Calculate the percentage by which the volume of the cylinder has - Custom-made 81913 On October 1, 2022, the customer ordered a custom-made kitchen from a carpentry company. Delivery time is 1 month. Four carpenters should work on the order in the workshop for 21 working days. Will they be able to deliver the kitchen on time if one of the
- Transferred 81895
The tin body transferred 150,000 J of heat, and its temperature dropped by 10°C. Calculate the mass of the tin body. (c of tin is 0.227 kJ/kg. °C). Enter the resulting weight in grams and round it to two decimal places.
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