Examples for 8th grade - page 29

  1. Car
    city The driver of a car is to get to 608 km distant city. From atlas found that 162 km will have to pass through the cities at average speed 48 km/h. Remainder of the journey pass outside the cities at average speed 116 km/h. Calculate how many hours it will t
  2. Coin
    mince How many 50-cent coins must be put in a row that next 50-cent coins after them (above) rolled on it axis?
  3. Height 2
    1unilateral_triangle Calculate the height of the equilateral triangle with side 38.
  4. Two diggers
    two-diggers There are two diggers. One digger digs a pit 46 hours second gidding 2 times faster. a) how long took to dig a pit second digger b) how long took dig together
  5. Trapezoid
    hexphitri Area of trapezoid is 135 cm2. Sides a, c and height h are in a ratio 6:4:3. How long are a,c and h? Make calculation...
  6. Bomber
    b52 Bomber flies 10 km at 600 km/h. At what horizontal distance from the target, must pilot drop the bomb to hit the target? Don't care about air resistance and consider the gravitational acceleration g=9.81 m/s2.
  7. Lorry
    lorry The lorry was loaded with 18 boxes of 15 kg. How many boxes with weight 18 kg can be loaded, if total load must be same?
  8. Divers
    diving 20-member group of divers carries the air for 15 hours of diving. 4 members of the expedition sick or wasn't came. How many hours is sufficient air to other divers?
  9. Grandson and granddad
    vnuk_dedo Grandson with grandpa they counted how many years have together. Their product is 365. How many years is the sum of their years.
  10. 30-60-90
    30-60-90 The longer leg of a 30°-60°-90° triangle measures 5. What is the length of the shorter leg?
  11. Two cars
    TwoCars From the town A to town B started two cars. The first at 7:00 at average speed 60 km per hour, the second at 10:00 at average speed 100 km per hour. The first car will not stay in B, and on the way back meet the second car at half way from A to B. At what.
  12. Iron fence
    fe One field of iron fence consists of 20 iron rods with square cross-section of 1.5 cm side and a long 1 meter. How much weight a field if the density of iron is 7800 kg/m3.
  13. Racer
    car_championship The first racer run at a speed 20 m/s and is 750 meters before the finish and ahead 79 meters before second competitor. At what speed must run the second racer to catch first racer at the finish line?
  14. Strawberries
    strawberries Father collects strawberries himself in 4 hours, son in 14 hours. How long will it take them along when dad comes to help son collect strawberries after 3 hours?
  15. Pyramid
    3d_shapes Cuboid ABCDEFGH has dimensions AB 3 cm, BC 4 cm, CG 5 cm. Calculate the volume and surface area of a triangular pyramid ADEC.
  16. Chicken
    sliepka I threw three chicken for a handful of grains and I noticed that it eat in a ratio of 8:7:6 and two of them grabbed 156 grains. How many grains have fought that chicken?
  17. Sawdust
    drevo_kmen_rez How many cubic centimeters of wood sawdust is created by cut the tree trunk with a diameter of 66 cm and when the gap width is 5 mm?
  18. Unions
    odbory_prdel Calculate how much money per year would go to the treasury of unions if 218 thousand employee join unions with an average net salary of 407 euros and if memberhip in union cost 1% of the net monthly salary.
  19. Cuboids in cube
    shapes How many cuboids with dimensions of 6 cm, 8 cm and 12 cm can fit into a cube with side 96 centimeters?
  20. Painter 3
    painter_2 Dad want to paint wall high 250 cm wide and 230 cm with wallpaper. How many meters must buy wallpaper if wallpaper width is 60 cm?

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