Math practice for 13 year olds - page 322 of 428

Number of problems found: 8549

The cast
The cast in the body of a regular quadrilateral pyramid with a base edge 60 cm long and 5 cm high is made of a material with a density of 7.8 g/cm cubic. Calculate its weight.
If we
If we increase the unknown number by 4%, we get 780. Determine the unknown number.
Dog chase
While hunting, the dog sees a hare in the bushes 20 meters ahead. The hare starts running, and the dog starts chasing it simultaneously. A hare runs at a speed of 39 km/h, and a dog at 45 km/h. In how many seconds does the dog catch up with the hare?
Cylinder hole
A cylinder-shaped hole with a diameter of 12 cm is drilled into a block of height 50 cm with a square base with an edge length of 20 cm. The axis of this opening passes through the center of the base of the cuboid. Calculate the volume and surface area of
Ruler case
A cylinder-shaped case is to be made for a ruler with the shape of a prism with a base in the shape of an equilateral triangle with a side length of 3 cm. What must be the smallest inner diameter of the housing? Determine the size to the nearest tenth of
Ice and water
We want to cover a rectangular rink with dimensions of 55 m and 25 m with a 4cm thick layer of ice. How many liters of water do we need if freezing water increases its volume by 10%?
Rhombus and diagonals
The rhombus area is 150 cm², and the ratio of the diagonals is 3:4. Calculate the length of its height.
Material transport
Two trucks were supposed to load the building materials in 10 days. After 6 days of work, the first car broke down, and the second one carried building materials for another 9 days. How many days would the first and second cars take the building materials
Image arrangement
Our task is to save the rectangular images with dimensions of 105 mm and 42 mm so that we cover the smallest square. What will be its size, and how many pictures do we need?
Apples 2
Dried apples contain 15% water. Fresh apples contain 80% water. How many kilograms of apples must we buy to get 3 kg of dried apples?
Fuel economy
How many kilometers is sufficient petrol in the cylinder fuel tank with a diameter of 40 cm and the base of tank length of 1 m when it is filled to 60%, and if the car consumes 15 liters per 100 km?
Diagonal of square
Calculate the side of a square when its diagonal is 10 cm.
Christmas
Father said, " Exactly after 56 hours, we will sit down at the Christmas Eve table." How was it, and what time was it, when Father said this sentence? They sat at the Christmas Eve table at exactly 6 PM.
Tower model
The tower's height is 300 meters, and its weight is 8000 tons. How high is the model of the tower's weight of 1 kg? (State the result in centimeters). The model is made from exactly the same material as the original no numbers need to be rounded. A result
Car overtaking
The car moved out of place at a speed of 60 km/h in 1.5 hours. The second car moved at a speed of 80 km/h. How long will it take to catch the first car, and how many kilometers will it drive?
Car meeting
It is 162 km from Nitra to Brezno. Two cars on the same route will leave both places simultaneously. A vehicle from Nitra travels at a speed of 60 km/h, and a car from Brezno travels at a speed of 75 km/h. How long and at what distance from Nitra will the
Incendiary cord
The flame spreads along the incendiary cord at a 30 m / min speed. How long must the cord be so that the launcher can move to a distance of 200 m if it moves at a speed of 4 m/s?
Motorcycle overtaking
A truck that is 6 m long travels at a speed of 66 km/h. A motorcycle traveling at a speed of 20 m/s overtakes him. Overtaking starts 16 m behind the car and ends 18 m in front of the car. How long does this overtaking last, and what track does the motorcy
Body meeting
From two places, M and N, 100 m apart, two bodies move simultaneously in the positive direction of the x-axis. A body moving from place M has a speed of 5 m/s, from place N 3 m/s. How long does it take for the first body to catch up with the second? What
Percentage conversion
When 17.2 kg is 94.9332%, how much kg is 66%?

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