Maths practice for 14 year olds - page 53 of 378
Number of problems found: 7551
- Staircase 81963
How long is the staircase railing with 17 steps if the step is 32 cm deep and 14.5 cm high? The last step does not count.
- Dimensions 81957
How many bricks are needed to build a wall that is 12 m long, 1.6 m high, and 47 cm wide if the dimensions of the brick are 30 x 15 x 7.5 cm and 5% of the wall volume is mortar?
- 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.
- 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?
- 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.
- Received 81933
The reward of CZK 4,220 was divided among 3 workers in such a way that the second received CZK 400 more than the first, and the third received 30% more than the second. How much did each get?
- 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.
- 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
- Revolutions 81906
How much energy was supplied by the flywheel of the device if its number of revolutions decreased from 1200 to 720 revolutions per minute if it has a moment of inertia of 71.3 kg/m²?
- Temperature 81892
By how much °C will the temperature of an iron key weighing 0.004 t change if it receives 360,000 J of heat? ( c of iron is 450 J/kg.°C )
- Temperature 81891
Calculate the mass heat capacity of a steel body weighing 2 kg, which was heated from an initial temperature of 15°C to 80°C by supplying 60 kJ of heat.
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