Maths practice for 12-year-olds - page 344 of 347

Number of problems found: 6923

Fuel consumption
Kia car has an average nafty consumption of 6.4 liters per 100 kilometers. What is the car range for a full tank of volume 71 liters?
Pipe
Steel pipe has a length of 1.7 meters. About how many decimetres is 1/3 less than 8/9 of this steel pipe?
Flags
How many different flags can be made from green, white, blue, red, orange, yellow, and purple materials if each flag consists of three stripes of different colours?
Carbon dioxide
Calculate how many grams of oxygen are in 59 grams of carbon dioxide CO₂. The relative atomic mass of oxygen is 16, and of carbon is 12.
Iron
Iron ore contains 61% iron. How much iron ore is needed to produce 29 tons of iron?
Air mass
What is the mass of the air in a classroom with dimensions 10 m × 3 m × 3 m? The density of air is 1.293 kg/m³.
Barrel of oil
The barrel of oil weighs 283 kg. When it molded 26% oil, it weighed 216 kg. What is the mass of the empty barrel?
Copper plate
Copperplate length 9 m and width 56 cm weigh 48.38 kg. What is the plate thickness if 1 m³ of copper weighs about 8700 kg?
Magnification of the square
If the side of a square is increased, the area increases by 57%. By what percentage was the side increased?
Circle and angle
What is the arc length of a circle with radius r = 432 dm corresponding to a central angle of 0.53 rad?
Promile
Calculate the 17.6 ‰ of 353.
Slovakia banks
It is an unwritten rule that the largest banks in Slovakia (by number of clients and balance sheet size) offer the worst and most expensive services. Many customers nevertheless remain loyal to the big three: SLSP, VUB, and Tatra banka. Calculate how many
Tesco Clubcard
František got quarterly billing vouchers for Tesco ClubCard, taking goods worth 6.5 Eur. Calculate the average monthly amount Tesco stores bought goods. Tesco ClubCard works for every Euro spent; you get one ClubCard point, which Tesco will convert to one
Human buying irrationality
I longer watch processors for Socket A on the secondhand market, Athlon XP 1.86GHz with a PR rating of 2500+ costs $7, and Athlon XP 2.16Ghz with a PR rating of 3000+ currently costs $16. Calculate: About what percentage of the Athlon XP 2.16Ghz is more p
Quiz
The tested student answered correctly on a 3/6 question. The wrong answer was 16. How many questions were answered?
Barrel with liquid
Barrel with obilím weight 123 kg. When it sheds 56% of obilia, ha weight 74 kg, what is the weight of an empty barrel?
Trapezium zoom
By how many times does the area of a trapezoid increase if all its sides and height are multiplied by 5?
Sumo competition
In a heaviest-man competition there were 5 competitors. The top three together weighed 369 kg. What is the minimum possible weight of the winner, given that contestants' weights are measured to the nearest kilogram?
Triangle angles
The angles α, β, and γ of triangle ABC are in the ratio 6:2:6. Calculate the size of each angle.
Degrees to radians
Convert magnitude of the angle α = 538°38'17" to radians:

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