Math practice for 13 year olds - page 190 of 434
Number of problems found: 8665
- Block-shaped 29941
Please calculate according to Pascal's law. Kerosene in a block-shaped metal tank reaches a height of 180 cm. Calculate the force acting on the bottom with dimensions of 1.5m and 3m if the density of kerosene is 820kg per M3.
- Pascal's law
Please calculate according to Pascal's law. Krupp's machines were known for their large size. In 1861, the inventor put a blacksmith's steam hydraulic press into operation in Essen. What was the cross-sectional area of the larger piston if a compressive f
- Calculations 29911
Calculations according to Pascal's law. A boiler with an internal wall area of 3.4 m² will be tested at a pressure of 0.9 MPa. Calculate the total compressive force acting on the boiler walls.
- Brass sphere
Find the weight of a brass ball with an outer radius of 12 cm and a wall thickness of 20 mm if the brass's density is 8.5 g/cm³.
- Connecting 29841
There is a horizontal distance of 9 km between two cities on the Croatian coast. The road connecting these two cities has a climb of 13 permille. What is the height difference between Croatian cities?
- Insulation
A special rubber pipe protector is used to insulate the supply pipes of solar collectors. The product with the description DNa20, thickness 25 mm, 2 m, corresponds to insulation for pipes with a diameter of 20 mm with a rubber layer thickness of 25 mm, wh
- Vertical 29801
The shadow of the building is 16 m long, and the shadow of the vertical meter rod is 0.8 m long at the same time. What is the height of the building?
- Triangular 29781
A triangular building plot is drawn on a 1:5,000 scale plan as a triangle with sides of lengths 32.5 mm, 23.5 mm, and 36 mm. Determine how many m of mesh are needed to fence the entire plot.
- Hectares
The rectangular land has 3 cm and 4.5 cm dimensions on the plan with a scale of 1:40,000. Find the area of the land in hectares.
- Consecutive 29761
Determine three consecutive natural numbers, the sum of which is 66.
- Father and son
When I was eight years old, my father was 30 years old. Today, my father is three times more than me. How old am I?
- Interest 29731
How much interest will the savings bank credit to the deposit of CZK 25,000 in 1 year at an annual interest rate of 2.5%?
- Volume of sphere
How many times does the volume of a sphere increase if its radius increases two times?
- The string
They cut 113 cm from the string and divided the rest in a ratio of 5:6.5:8:9.5. The longest part measured 38 cm. Find the original length of the string.
- Extending square garden
Mrs. Petrová's garden had a square shape with a side length of 15 m. After its enlargement by 64 m² (square), it became a square again. How many meters has the length of each side of the garden been extended?
- Soccer balls
Pupils in one class want to buy two soccer balls together. If each of them brings 12.50 euros, they will miss 100 euros; if each brings 16 euros, they will remain 12 euros. How many students are in the class?
- Gears
The front gear on the bike has 32 teeth, and the rear wheel has 12 teeth. How many times does the bike's rear wheel turn if you turn the right pedal 30 times? What distance will you go if the circumference of the bicycle wheel is 250 cm?
- Therefore 29661
Věra wants to welcome her friend Nada, who will arrive by train at 8:22 AM. Therefore, he leaves home 1.2 km from the station at 8:00 AM and travels at a speed of 3.6 km/h. Will he arrive on time?
- Powerful 29651
The first machine can sow a field in 12 hours. The second, more powerful machine in 8 hours. How many hours was the field sown if workers deployed both machines, but the second machine started working 2 hours later than the first machine?
- Natural fertilizer
The gardener fertilized the rectangular garden measuring 120m and 60m with 16kg of natural fertilizer. Natural fertilizer contains 45% organic matter. How much organic matter falls on 1 m² of the garden?
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