Math practice for 13 year olds - page 202 of 431
Number of problems found: 8620
- Reconstructing 23991
Three groups take turns reconstructing one piece of highway. The first group would finish the job themselves in 40 working days. The second group is in 24 working days, and the third group is in 30 working days. How many days do you do it together?
- Three-fifths 23961
Three-fifths of the orchard trees are apple trees. One-third are cherry trees. The remaining five trees are pear trees. How many trees are in total growth in the orchard?
- Observation tower
The observation tower has a height of 105 m above sea level. The ship is aimed at a depth angle of 1° 49' from the tower. How far is the ship from the base of the tower?
- Pentagonal prism
The regular pentagonal prism is 10 cm high. The radius of the circle of the described base is 8 cm. Calculate the volume and surface area of the prism.
- The shadow
The shadow of a 1 m high pole thrown on a horizontal plane is 0.8 m long. At the same time, the shadow of a tree thrown on a horizontal plane is 6.4 m. Determine the height of the tree.
- Diameters: 23901
When paying, we use euro coins with the following diameters: The 10-cent coin has a diameter of 19.75 mm. The 20-cent coin has a diameter of 22.25 mm. The 50-cent coin has a diameter of 24.25 mm. Find out in what ratio the diameters of these coins are.
- Quadrilateral 23891
A cylinder with the maximum possible base was ground from a wooden regular quadrilateral prism (edge 2.8 cm, height 7.5 cm). What percentage of the material was wasted as waste? What percentage would it be if the height of the prism were twice as large?
- 3 pupils
Three pupils cleaned 10 meters of the stream in 1 hour. How many meters of the stream will clean 18 students in 4 hours?
- Complete 23811
We ordered two parties of workers to replace the windows and doors. The first group would complete the task in 15 days. The second in ten days. How many days will they be able to exchange it together?
- Administrator 23801
The administrator of the castle is trying to estimate how many square meters of sheet metal will be needed for the new roof of the tower. The roof has the shape of a cone. The castle administrator knows that the tower's diameter is 4.6 meters and its heig
- Measures 23791
The volume of the block is 144 cm³. The base measures 3 cm and 4 cm. How big is the body diagonal?
- Centimeter 23781
Calculate the diameter of a cylinder 7.5 dm high with a volume of 0.6 hl. Express the result to the nearest centimeter.
- Triangular prism
Calculate the surface of a regular triangular prism; the base's edges are 6 cm long, and the height of the prism is 15 cm.
- Five tractors
Five tractors plow the fields in 4.8 hours. How long will it take to plow the field when, after an hour and a half of work, two tractor drivers have been called up for another task?
- Determine 23741
Adam and Eve live 20 km apart. They are going to a meeting. Adam moves at a speed of 2 km/h faster than Eva. They will meet in one and a half hours. Determine their speeds.
- Kilometers 23721
Eva left the cinema at a speed of 4 km/h. Half an hour later, Adam left after her with the mobile phone that Eva had forgotten at the cinema. It was moving at a speed of 6 km/h. How long will it take Adam to catch up with Eva, and how many kilometers from
- Two hemispheres
In a wooden hemisphere with a radius r = 1, the carpenter created a hemispherical depression with a radius r/2. The bases of both hemispheres lie in the same plane. What is the surface of the created body (including the surface of the depression)?
- Quadrilateral 23701
We know a regular quadrilateral pyramid's base diagonal length of u = 4 cm. The height of the pyramid is v = 5cm. Calculate the size of the side edge and the base edge of the pyramid.
- Banknotes 23691
Dad paid for the computer with banknotes worth 500 and 1,000 CZK. The number of banknotes was 56, and the price of the computer was CZK 44,000. How many banknotes did he have?
- 4-member 23681
A four-member group planned to paint the school for ten days. After two days, one member fell ill. If they worked with the same effort, how many days were the school painted?
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