Math practice for 13 year olds - page 315 of 420

Number of problems found: 8400

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
Percentage conversion
When 17.2 kg is 94.9332%, how much kg is 66%?
Car meeting
Cars from two cities, A and B, 90 km apart, drove towards each other simultaneously. The car from city A had a constant speed of 72 km/h, and the car from city B had a speed of 90 km/h. How long and how far from city B will they meet?
Frameworks is bad
Calculate how much percent will increase an HTML document's length if any ASCII character is unnecessarily encoded as a hexadecimal HTML entity composed of six characters (ampersand, grid ; , x, two hex digits, and the semicolon). Ie. space as: &; x20
Isosceles - isosceles
It is given a triangle ABC with sides /AB/ = 3 cm /BC/ = 10 cm, and the angle ABC = 120°. Draw all points X such that the BCX triangle is an isosceles and triangle ABX is an isosceles with the base AB.
Mushrooms
Fresh mushrooms contain 90% water, dried only 12%. How many kilograms of fresh mushrooms are needed for 5 kg dried?
Square vs rectangle
A square and a rectangle have the same areas. The rectangle's length is nine greater, and the width is six less than the side of the square. Calculate the side of a square.
Trapezium 2
The trapezium has an area of 24 square cm. How many different trapeziums can be formed?
Coal mined
The monthly plan exceeded 17,000 tons of coal at the mine by 12.5%. How many tons of coal did they mine?

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