Examples for 8th grade - page 30

  1. Crown
    2_kcs Siblings collect a 2-crowns and 5-crowns. Together have 80 coins with a total of value 310 crowns. How many saved two-crowns and how many five-crowns?
  2. The body
    body_cubes The body on the figure consists of cubes with an edge length 10 cm. What surface has this body?
  3. Mother and daughter
    mom_daughter Three years ago mother was three times older than daughter. After nine years she will be only twice old. How old is mother (and daughter)?
  4. Triangle
    trangle_nice Calculate heights of the triangle ABC if sides of the triangle are a=48, b=81 and c=98.
  5. Map 2
    world_map_atlas At what scale is made map if the distance 6.8 km corresponds on the map segment 4 cm long?
  6. Cube - wall
    cubes_2 V kocke ABCDEFGH je ?. Aký je povrch kocky?
  7. Father and son
    father_sin Father is three times older than his son. 12 years ago father was nine times older than the son. How old are father and son?
  8. Area 4gon
    4gon Calculate area of 4-gon, two and the two sides are equal and parallel with lengths 7, 15, 7 and 15. Inner angles are 45°, 135°,45°, 135°.
  9. Cuboid 5
    drevo_1 Calculate the weight of the cuboid with dimensions of 12 cm; 0.8 dm and 100 mm made from spruce wood (ς = 550 kg/m3).
  10. VAT
    tax VAT is a tax which the state artificially betrays goods and services for final consumption. VAT in Slovakia is 20%. Calculate how much percent pay less tax residents of Switzerland, when VAT is only 8%.
  11. The professor's birthday
    prof_einstein Professor of mathematics had 36 birthdays. The director congratulated him. The professor asked the director: "And how old are you?" The director replied: "I'm exactly twice as many years than you were when I was old as to you today." How old is the direc
  12. Rising price
    book The book first become more expensive by 5 euros. New price was later increased by 13%. After the second price increase book cost 47 euros. What was the original price of the book?
  13. Ladder
    studna 7.4 meters long ladder is leaning against the wall of the well and its lower end is 1.1 meters from this wall. How high from the bottom of a well is the top edge of the ladder?
  14. Gon functions
    quadrants Decide which of the numbers (values ​​of trigonometric functions) are positive and which are negative (or zero). Positive mark +1 and negative -1.
  15. Carbon dioxide
    co2 Calculate how many grams of oxygen are in 126 g of carbon dioxide CO2. Relative atomic mass of oxygen is 16 and of carbon is 12.
  16. Diamond ABCD
    kosoctverec2 In the diamond ABCD is the diagonal e = 24 cm and size of angle SAB is 28 degrees, where S is the intersection of the diagonals. Calculate the circumference of the diamond.
  17. ISO Triangle V2
    triangle_3 Perimeter of RR triangle (isosceles) is 474 m and the base is 48 m longer than the arms. Calculate the area of this triangle.
  18. Password
    codes The voltage station is every day changing the master password, which consists of three letters. Code generation process does not change and is based on the following procedure: The following letters (A) to (I) correspond to different numbers from 1 to 9. I
  19. Building base
    base_of_building Excavation for the building base is 350x600x26000. Calculate its volume in m3.
  20. Compare II
    powers Which of the numbers 158, 815 is greater?

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