Examples for 8th grade - page 10

  1. 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?
  2. Pump
    pumpa What power has a pump output to move 4853 hl of water to a height of 31 m for 8 hours?
  3. 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?
  4. 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?
  5. 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.
  6. 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?
  7. 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?
  8. 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.
  9. Cylinder - basics
    cylinder Cylinder with base radius r = 45 dm and height h=22 dm. Calculate:
  10. Tape
    mg Video is 153% more expensive than tape recorder. How many percent is tape recorder less expensive than video?
  11. 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.
  12. 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.
  13. Hollow sphere
    Xmas_ball Calculate the weight of a hollow tungsten sphere (density 19.3 g/cm3), if the inner diameter is 14 cm and wall thickness is 3 mm.
  14. Cone
    truncated_cone_1 Circular cone with height h = 29 dm and base radius r = 3 dm slice plane parallel to the base. Calculate distance of the cone vertex from this plane, if solids have the same volume.
  15. Tourists
    hiking From the cottage started first group of tourists at 10:00 AM at speed 4 km/h. The second started after them 47 minutes later at speed 6 km/h. How long and how many kilometers from the cottage will catch the first group?
  16. Triangular prism
    TriangularPrism Plane passing through the edge AB and the center of segmet CC' of regular triangular prism ABCA'B'C', has angle with base 39 degrees, |AB| = 3 cm. Calculate the volume of the prism.
  17. Tower
    cone_roof How many m2 of copper plate should be to replace roof of the tower conical shape with diameter 24 m and the angle at the vertex of the axial section is 144°?
  18. Diagonals of the rhombus
    diagonals_rhombus Calculate height of rhombus whose diagonals are 12 cm and 19 cm.
  19. Prism
    cuboid_2 Three cubes are glued into prism, sum of the lengths of all its edges is 115 cm. What is the length of one edge of the original cube?
  20. Profitable bank deposit 2012
    eurocoins Calculate the value of what money lose creditor with a deposit € 9500 for 4 years if the entire duration are interest 2.6% p.a. and tax on interest is 19% and annual inflation is 3.7% (Calculate what you will lose if you leave money lying idle at negative

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