# - 7th grade (12y) - math problems

#### Number of problems found: 2784

- Rotating cone II

Calculate area of surface of rotating cone with base radius r=19 cm and height h=9 cm. - Average

The average of 5 numbers is 108. What is its sum? - Bulbs

In the box are 6 bulbs with power 75 W, 14 bulbs with power 40 W and 15 with 60 W. Calculate probability that a randomly selected bulb is: - Rectangles

How many rectangles with area 8713 cm^{2}whose sides are natural numbers are? - Guess number

With what number should be divided, number 9727 to be reduced by 70%? - Secret number

Determine the secret number n, which reversed decrease by 16.4 if the number increase by 16.4. - Earth parallel

Earth's radius is 6370 km long. Calculate the length parallel of latitude 50°. - Tree trunk

Calculate the average tree trunk with a circumference of 149 cm. - Clock

How long is the trajectory of the second hand of hours for day, if it is 15 mm long? - Seedcake

Seedcake costs 44 cents. How many minimum seedcakes we must buy that we can pay in cash only whole euros? - Equilateral triangle

Calculate the side of an equilateral triangle if its area is 892 mm^{2}. - Circle

How big is an area of a circle if its circumference is 51.2 cm? - Truncated cone

Calculate the volume of a truncated cone with base radiuses r_{1}=13 cm, r_{2}= 10 cm and height v = 8 cm. - Copper sheet

The copper plate has a length of 1 m, width 94 cm and weighs 9 kg. What is the plate thickness, if 1 m^{3}weighs 8715 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 3.9 liters per 100 kilometers. What is the range of the car for 179 euros if fuel costs 1.3 EUR/liter, if the tank has a volume of 55 liters? - Fuel consumption

Škoda car has an average diesel consumption of 5.9 liters per 100 kilometers. What is the car range for a full tank of volume 70 liters? - Forest nursery

In Forest nursery plant one pine to 1.9 m^{2}. Calculate how many plants are planting in area 362 acres. - Pipe

Steel pipe has a length 2.5 meters. About how many decimetres is 1/3 less than 4/8 of this steel pipe? - Flags

How many different flags can be made from colors red, yellow, blue, green, white to consist of three different colors?

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