Examples for 8th grade - page 17

  1. Election mathematics
    statny-znak-sr_1 In elections, 6 political parties received this shares of voters: strana A 69.4 %strana B 11.2 %strana C 10.2 %strana D 7.6 %strana E 1.6 % Calculate what the shares acquired in the parliament, if a quorum is 5%.
  2. Cardboard box
    krabicka We want to make a cardboard box shaped quadrangular prism with rhombic base. Rhombus has a side of 5 cm and 8 cm one diagonal long. The height of the box to be 12 cm. The box will be open at the top. How many square centimeters cardboard we need, if we cal
  3. 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
  4. Sphere A2V
    sphere3 Surface of the sphere is 306 m2. What is its volume?
  5. Steamship
    parnik Between the two ports on the river is going steamship. The journey there and back takes 14:49. Downstream steamship traveling at 21 km/h, upstream 9 km/h. What is the distance between the ports?
  6. Leveling
    quattro Calculate how many 25 kg bags of leveling concrete must be purchased if we leveling room 28 m2 to the "height" 12 mm if consumtion is 1.7 kg per square meter and millimeter thickness.
  7. Wheat
    field_1 The rectangle shaped field with dimensions 979 m and 540 m harvested last year was 2775 q wheat. (1 q = 1 quintal = 100 kg). During the year, it was necessary to fix the pipe and therefore did kick wide 6 m parallel to the side of the field 540 m, where no
  8. Blueberries
    boruvky Marie earns 1.8 liters of blueberries for 1.2 hours, Peter 2.6 liters for 1.2 hours. How long have earns together one liter?
  9. Three workers
    three_workers Three workers A, B, C have to work on a specific task. Workers A and B completed whole task in 25 days, B together with C for 16 days, A together with C for 10 days. How long it would take to complete the task every one of them alone? How long it would.
  10. Heron backlaw
    heron_math Calculate missing side in a triangle with sides 33 and 27 and area 118.3.
  11. Wiring
    install_pipes Conduit has a cross section 492 mm. Maybe put it into 5 conductors with a cross section S2 $mm2?
  12. Two balls
    balls-inside-cylinder Two balls, one 8cm in radius and the other 6cm in radius, are placed in a cylindrical plastic container 10cm in radius. Find the volume of water necessary to cover them.
  13. Triangle angles
    triangles_2 The angles α, β, γ in triangle ABC are in the ratio 10:5:6. Calculate size of angles.
  14. Shooter
    terc_1 The shooter fired to a target from distance 9 m The individual concentric circle of targets have a radius increments 1 cm (25 points) by 1 point. Shot was shifted by 16'(angle degree minutes). How many points should win his shot?
  15. Compass
    wind_rose What angle are between directions W (West) and SE (SouthEast) on the compass?
  16. Scrap
    chair_bad From 8 products are 2 scrap. What is the probability that the random pick of 2 products have no defective product?
  17. XY triangle
    triangle Determine area of triangle given by line -7x+7y+63=0 and coordinate axes x and y.
  18. Coin and die
    die Flip a coin and then roll a six-sided die. How many possible combinations are there?
  19. Pumps
    water_pump Pump that draws water at velocity 3.5 liters per second water from a construction trench take 35 minutes. a) Find out how many minutes the water would run out of the trench pump that draws 7.4 liters of water per second. b) What is the pumping velocity wo
  20. Hollow sphere
    sphere_2 Steel hollow sphere floats on the water plunged into half its volume. Determine the outer radius of the sphere and wall thickness, if you know that the weight of the sphere is 0.5 kg and density of steel is 7850 kg/m3

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