Examples for 8th grade - page 9

  1. Rates
    gas_meter When gas consumption, the consumer may choose one of two rates: rate A - which pays 0.4 € per 1 m3 of gas a flat monthly fee of 3.9 € (regardless of consumption) rate B - which pays 0.359 € per 1 m3 of gas a flat monthly fee of 12.5 € From what monthl
  2. Rotation of the Earth
    earth_1 Calculate the circumferential speed of the Earth's surface at a latitude of 61°​​. Consider a globe with a radius of 6378 km.
  3. 2nd class variations
    cards From how many elements you can create 6972 variations of the second class?
  4. Camel
    camels Camel owner wants to get out of the city into oasis. He bought 3000 bananas, which wants to sell in oasis. However oasis from the city divided 1,000 kilometers of desert. Camel can carry at one time up to 1000 bananas, and for every kilometer traveled, ea
  5. Negative percentage
    trabant In 2004, the company had a loss of 40900 Euros. Two years later he was already in profit 48900 Eur. Calculate what percentage of the company increased profits in this two years.
  6. Cube - angles
    cube_diagonal_1 Calculate angle between the wall diagonal and cube base. Calculate the angle between the cube body diagonal and cube base.
  7. Saving
    cars Allen save € 2860 to buy a car. Yet it lacks save 55% of the car price. How much is the car?
  8. Plastic pipe
    pvc-trubka Calculate weight of the plastic pipe with diameter d = 70 mm and length 380 cm if the wall thickness is 4 mm and the density of plastic is 1367 kg/m3.
  9. Pyramid roof
    pyramid_roof 1/3 of area of ​​the roof shaped regular tetrahedral pyramid with base edge 9 m and height of 4 m is already covered with roofing. How many square meters still needs to be covered?
  10. Prism X
    Cuboid_simple The prism with the edges of the lengths x cm, 2x cm and 3x cm has volume 20250 cm3. What is the area of surface of the prism?
  11. Pump
    pumpa What power has a pump output to move 4853 hl of water to a height of 31 m for 8 hours?
  12. Workers
    workers Two workers fulfill a certain task when working together for 5 days, the first if he worked himself done work in 13 days. How many days will do whole job a second worker?
  13. Pizza
    pizza_2 Pizza with a diameter 50 cm have weight 559 g. What diameter will have a pizza weighing 855 g if it is make from the same cloth (same thickness....) and same decorated?
  14. Gear wheels
    gear Two gear wheels, which fit together have number of teeth z1=120 and z2=80. Calculate the speed of the first wheel, if the second wheel rotates 1669 revolutions per minute.
  15. Rhombus
    rhombus_1 Find the length of the other diagonal and area of rhombus. The perimeter of a rhombus is 40 cm and one of the diagonals is of length 10 cm.
  16. Acid
    acid_1 The barrel is 199 litres of 38% acid. How many percent acid occurs when 61 litres revoke and replace it with the same amount of water?
  17. Climb
    Mazda_RX7_1 On the road sign, which informs the climb is 8.7%. Car goes 5 km along this road. What is the height difference that car went?
  18. Cylinder - basics
    cylinder Cylinder with base radius r = 45 dm and height h=22 dm. Calculate:
  19. Tetrahedral pyramid
    jehlan_1 Calculate the volume and surface area of a regular tetrahedral pyramid, its height is $b cm and the length of the edges of the base is 6 cm.
  20. ISO triangle
    rr Calculate the area of an isosceles triangle KLM if the length of its sides are in the ratio k:l:m = 4:4:3 and has perimeter 377 mm.

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