- 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.
The average of 5 numbers is 108. What is its sum?
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:
How many rectangles with area 8713 cm2 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.
How long is the trajectory of the second hand of hours for day, if it is 15 mm long?
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 mm2.
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 r1=13 cm, r2 = 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 m3 weighs 8715 kg?
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 m2. Calculate how many plants are planting in area 362 acres.
Steel pipe has a length 2.5 meters. About how many decimetres is 1/3 less than 4/8 of this steel pipe?
How many different flags can be made from colors red, yellow, blue, green, white to consist of three different colors?