Maths practice for 12-year-olds - page 306 of 309
Number of problems found: 6169
- Bulbs
In the box are 6 bulbs with power 75 W, 14 bulbs with power 40 W, and 15 with 60 W. Calculate the probability that a randomly selected bulb is: - Guess number
With what number should be divided, number 9727 to be reduced by 70%? - Secret number
Find the secret number n, which reversed decreases by 16.4 if the number increases by 16.4. - Clock
How long is the trajectory of the second hand of hours for day, if it is 15 mm long?
- Earth parallel
Earth's radius is 6377 km long. Calculate the length parallel to latitude 75°. - Seedcake
Seedcake costs 44 cents. How many minimum seedcakes must we buy that we can pay in cash, only whole euros? - Equilateral triangle
Calculate the side of an equilateral triangle if its area is 886 mm². - Circle
How big is the area of a circle if its circumference is 51.2 cm? - Truncated cone
Calculate the volume of a truncated cone with base radiuses r1=20 cm, r2 = 10 cm, and height v = 14 cm.
- Copper sheet
The copper plate has a length of 2.2 m, width 92 cm, and weighs 5.6 kg. What is the plate thickness if 1 m³ weighs 8732 kg? - Cylinder
Calculate the dimensions of rotating cylindrical containers with volume 2 l if the container's height is equal to the base's diameter. - Car range
Kia has an average diesel consumption of 5 liters per 100 kilometers. What is the range of the car for 135 euros if fuel costs 1.4 EUR/liter, if the tank has a volume of 51 liters? - Forest nursery
In the Forest nursery plant, one birch to 1.2 m². Calculate how many plants are planted in the area of 738 acres. - Fuel consumption
Mazda car has an average nafty consumption of 4.2 liters per 100 kilometers. What is the car range for a full tank of volume 73 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, so each flag consists of three different colors? - Carbon dioxide
Calculate how many grams of oxygen are in 58 grams of carbon dioxide CO2. The relative atomic mass of oxygen is 16, and of carbon is 12. - Iron
Iron ore contains 54% iron. How much iron ore is needed to produce 23 tons of iron? - 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?
The USA hit an extreme heat wave. Calculate the percentage of the air temperature change from normal summer temperature 23 °C to 40 °C.Do you have homework that you need help solving? Ask a question, and we will try to solve it. Solving math problems.
