# - 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 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.
• 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 mm2.
• 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 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?
• 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 m2. 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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