Examples for 8th grade - page 15

  1. Posters
    posters Column with posters in the form of a cylinder is 2 m high and its diameter is 1.7 m. What is the content area for which it is possible to stick posters?
  2. Wood in the forest
    drevo The amount of wood in the forest was estimated at 6000 m3. How much wood will be in forest after 2 years if the annual growth of wood is 2.5% each year and logging 30 m3 each year?
  3. Sugar - cuboid
    kocky_cukor Pejko received from his master cuboid composed of identical sugar cubes with count between 1000 and 2000. The Pejko eat sugar cubes in layers. The first day eat one layer from the front, second day one layer from right, the third day one layer above. Yet i
  4. Free fall
    volny_pad Lloyd fall from height 7 m. Calculate the speed he hit the ground when falling with acceleration g = 9.81 m/s2
  5. Hexagonal pyramid
    Hexagonal_pyramid Calculate the volume and the surface of a regular hexagonal pyramid with a base edge length of 3 cm and a height of 5 cm.
  6. Cylinder - h
    cylinder_2 Cylinder volume is 215 cm3. Base radius is 2 cm. Calculate the height of the cylinder.
  7. Hexagon - MO
    6uholnik_nepravidelny The picture shows the ABCD square, the EFGD square and the HIJD rectangle. Points J and G lie on the side CD and is true |DJ|
  8. Height
    thales_law Is right that in any right triangle height is less or equal half of the hypotenuse?
  9. n-gon
    x-gon What is the side length of the regular 5-gon inscribed in a circle of radius 12 cm?
  10. Trains
    trains On double track line between stations K and M went against each other two trains. The first train passed the distance between stations for 3.5 hours, the second, which had an average speed of 12 km/h more passed for 3.05 hours. Calculate the distance betw
  11. Reservoir + water
    cuboid_water Reservoir completely filled with water weighs 12 kg. After pouring off three quarters of the amount of water weights 3 kg. Calculate the weight and volume of the reservoir.
  12. Greek railwayman
    greecerails_1 Wesley works for the Slovak railways since 1986. His salary is 864 €. His colleague, Evgenias works in the Greek State Railways from 1991. Earns 5010 € per month. Calculate how many hours a day must Evgenias work to earn as much as Wesley and if they w
  13. Right triangle
    right_triangles Calculate the missing side b and interior angles, perimeter and area of ​​a right triangle if a=10 cm and hypotenuse c = 16 cm.
  14. Lead cube
    pb_cube Calculate the edge of the cube made ​​from lead, which weighs 19 kg. The density of lead is 11341 kg/m3.
  15. Moving
    movie Vojta left the house at three o'clockat 4 km/h. After half hour later went from the same place Filip by bicycle at speed 18 km/h. How long take Tilip to catch up Vojta and how far from the house?
  16. Rhombus
    rhombus2 Internal angles of rhombus is in ratio 2:3. How many times is the shorter diagonal longer than side of rhombus?
  17. Water inlets
    pipe Inlet valve with a flow rate of 12 liters per second is filled tank for 72 minutes. How long take to fill full tank if we open one more such valve half an hour after?
  18. MO - triangles
    metal On the AB and AC sides of the triangle ABC lies successive points E and F, on segment EF lie point D. The EF and BC lines are parallel and is true this ratio FD:DE = AE:EB = 2:1. The area of ABC triangle is 27 hectares and line segments EF, AD, and DB se
  19. Scrap
    chair_bad From 6 products are 3 scrap. What is the probability that the random pick of 2 products have no defective product?
  20. Train
    High-Speed-Train A passenger train traveled for 2 hours 74 km. 3.1 hours after its departure started fast train and caught it on 186 km. How many km/h is different its average speeds?

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