Examples for 8th grade - page 73

  1. The factory
    hutny material The factory ordered 500 hexagonal steel bars of square section with 25 mm side. How many cars with a load capacity of 3 tonnes will be needed for bars move if the steel density is 7,850 kg.m-3?
  2. Eight palm
    palma There grows 8 palms by the sea. At the first sitting one parrot, on second two, on third sits four parrots on each other twice the previous parrots sitting on a previous palm. How many parrots sitting on eighth palm?
  3. Cuboid - edges
    kvader_abc The cuboid has dimensions in ratio 4: 3: 5, the shortest edge is 12 cm long. Find: (A) the lengths of the remaining edges, (B) the surface of the cuboid, (C) the volume of the cuboid
  4. Three figures - numbers
    numbers34 The sum of three numbers, if each is 10% larger than the previous one, is 662. Determine the figures.
  5. Right triangle eq2
    rt_2 Hypotenuse of a right triangle is 9 cm longer than one leg and 8 cm longer than the second leg. Determine the circumference and area of a triangle.
  6. Gasoline tank cylindrical
    cisterna What is the inner diameter of the tank, which is 8 m long and contains 40 cubic cubic meters of gasoline?
  7. Theatro
    divadlo_1 Theatrical performance was attended by 480 spectators. Women were in the audience 40 more than men and children 60 less than half of adult spectators. How many men, women and children attended a theater performance?
  8. Mr and Mrs
    clocks2_8 Mr. Calda and Mrs. Cald have a total of 139 years. How many years have when we know that Mr. Calda is 9 years older than Mrs. Cald
  9. Trams
    tramvaje Two trams started at the same time from the same place. One tram journey takes 30 minutes and the second 45 minutes to its final stop. How long will trams meet again?
  10. Driver
    truck_2 The driver of the supply car reckoned that at the average speed of 72 km/h arrives to the warehouse for 1 1/4 hours. After 30 km however unintentionally drove to the gas station and have ten minutes delay. At what average speed would have to go the rest.
  11. Family
    sediny Mom is 39 years old. Karl is eight years and Paul 4 years. For many years mother would old just like two children together?
  12. Image scale
    mazanina The actual image dimensions are 60 cm x 80cm and has a reduced size 3 cm x 4 cm. At what scale the image was reduced?
  13. Coins
    coins Denis and Zdeno together have 97 coins. If Denis had 4 coins less than he has now, the number of the coins would be in the ratio 14: 17. Determine the number of coins owned by Denis and Zdeno.
  14. Assistant
    psaci-stroj Assistant rewrote 15% of the entire manuscript in 12 hours. How many hours must still write to rewrite the rest of the manuscript?
  15. Family parcels
    map_4 In father will he divided the land so that the older son had three bigger part than younger son. Later elder son gave 2.5 ha field to younger and they had both the same. Determine the area of family parcel.
  16. Cableway
    cable-car Cableway has a length of 1800 m. The horizontal distance between the upper and lower cable car station is 1600 m. Calculate how much meters altitude is higher upper station than the base station.
  17. Class 9A
    boy On the final certificate have one quarter of the class 9A mark "C" of mathematics, seventh mark "C" from the Czech language and two students failed in chemistry. How many students attend class 9A?
  18. Hydrochloric acid
    hcl Determine the concentration of which must have a solution of hydrochloric acid that mixing 10 l of the solution with 8 liters of 26% solution to get the solution with a concentration of 50%?
  19. Base, percents, value
    percent_1 Base is 344084 which is 100 %. How many percent is 384177?
  20. Right triangle ABC
    right_triangle_2 Calculate the perimeter and area of a right triangle ABC, if you know the length of legs 4 cm 5.5 cm and 6.8 cm is hypotenuse.

Do you have interesting mathematical example that you can't solve it? Enter it and we can try to solve it.

To this e-mail address we will reply solution; solved examples are also published here. Please enter e-mail correctly and check whether you don't have a full mailbox.