Examples for 8th grade - page 48

  1. Concentration
    ocet_1 How 0.5 liters of 8% vinegar diluted to a concentration of 20 hundredths % of vinegar? How many liters of water must be pour?
  2. Water pool
    basen_2 Pool with volume 990hl completely filled, if water flows by one tap 8 hours and by second tap 6 hours. First tap give 10hl more than second per hour. How many hl flows in each of them in an hour?
  3. Reservoir
    cylinder_Au 6 m long reservoir has a diameter of 2.2 m. What is its surface area in square meters?
  4. Chord AB
    chord_3 What is the length of the chord AB if its distance from the center S of the circle k(S, 71 cm) is 27 cm?
  5. Circle sector
    vysec Circular sector with a central angle 10 ° has area 254 cm2. Calculate its radius r.
  6. Building base
    base_of_building Excavation for the building base is 350x600x26000. Calculate its volume in m3.
  7. For thinkings
    glass_cubes The glass cube dive into the aquarium, which has a length of 25 cm, width 20 cm and height of 30 cm. Aquarium water rises by 2 cm. a) What is the volume of a cube? b) How many centimeters measure its edge?
  8. The cylindrical container
    cylinder_1 The container has a cylindrical shape the base diameter 0.8 meters has a content area of the base is equal to the content area of the shell. How many full liters of water can be poured maximally into the container?
  9. Car rent
    car_5 Rental cars are paid a fixed daily fee plus 16 cents for each kilometer traveled. Samuel want to rent a car for a day and worked out that will pay 175 euros. When paying he got a 20% discount on the daily fee, the cost per kilometer is unchanged. Samuel th
  10. Rhombus 2
    koso Calculate the area of rhombus which has a height v=48 mm and shorter diagonal u = 60 mm long.
  11. Sales stores
    map_2 The first sales store passed the 1/3 and the second 2/5 of the total amount of goods.In third store passed the 2/3 rest of the goods. The remaining 40 kg of goods put into fourth store. How many kilograms of goods pass to a third store?
  12. Unknown number 10
    num_1 Number first increased by 30%, then by 1/5. What percentage we've increased the original number?
  13. Square and circle
    circle_square Into square is inscribed circle with diameter 10 cm.What is difference between circumference square and circle?
  14. Again saw
    rectangle_in_circle From the trunk of the tree we have to a sculpture beam with rectangular cross-section with dimensions 128 mm and 140 mm. What is the trunk smallest diameter?
  15. Square roots
    roots What is equal to the product of the square roots of 540225?
  16. Cars
    car_red Cars started at 7:00 AM. From point A car run at 40 km per hour, from B car run 70 km per hour. Between A and B is 250 km long road. When and where will meet (measured from point A)?
  17. Rectangle - sides 3
    stvorec If in the rectangle ABCD we enlarge the side a by 5 cm and decrease the side b by 2 cm, the rectangle area will be reduced by 5 cm². When we decrease the length of the side a by 4 cm and and at the same time we increase the length of side b by 3 cm we incr
  18. Two cars
    car_racing Car A1 goes at average speed of 133 km/h and the second car A2 goes at 128 km/h. How many second will it take car A1 to circulate car A2? Assume that both cars are 4.7 meters long and the safety gap between cars is 2.7 meters.
  19. Flowerbed 2
    flowerbed Around the square flower bed in a park is sidewalk 1.4 m wide. The area of ​​this sidewalk is 125 m2. What is the area of the flowerbed?
  20. Tram
    tramvaj-skoda In the three-part tram went 109 passengers in front of others, 92 after others and in the middle half of all. How many passengers went in tram total?

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