Examples for 8th grade - page 54

  1. Surveyor
    totalna-stanica Calculate the area of ​​what may vary rectangular, if it focused by surveyor and found the dimensions 18 x 15 m while in each of the four joint points can be position deviation 25 cm?
  2. Sisters
    cycle Sisters Zuzka Lenka and Vierka has save for a new bike. Zuzka save € 90, Lenka save € 90 and Vierka save € 82. Missing 30% gave them their mother. What is the price of the bike?
  3. Painting
    basen_7 To paint the pool with dimensions: 2 meters depth, 3m x 4m we bought paint to 50 meters square. How many "paint" will be a waste?
  4. Number
    percent What number is 20 % smaller than the number 198?
  5. Trapezium
    trapezium_1 The area of trapezium is 35cm2 find its altitude if the bases are 6cm and 8cm.
  6. Copper plate
    plech Calculate the thickness of the copper plate with a density 8.7 g/cm³ measuring 1.5 meters and 80 cm and its weight is 3.65 kg
  7. Circle and hexagon
    circles_fun Calculate the radius of a circle whose circumference is 8.4 cm longer than the circumference of the inscribed regular hexagon.
  8. Cleaners
    clean Milan would clean up the room for 2.5 hours, Eric would take 10 hours. How long they swept the room together?
  9. Water well
    studna Drilled well has a depth 20 meters and 0.1 meters radius. How many liters of water can fit into the well?
  10. Prism
    prism Base of perpendicular triangular prism is a right triangle with cathetuses 4.5 cm and 6 cm. What is the surface of the prism, if its volume of 54 cubic centimeters.
  11. Pool
    inlet Pool is filled with two water supply. The first supply fill pool for nine hours, the second for six hours. How many hours will take fill the pool when the water flows in through the first supply 3 hours and then we will open a second supply?
  12. Mother and daughter 2
    mother_baby The mother is 40 years older than her daughter. How old is the mother if her age is eight thirds age of daughter?
  13. Efficiency
    engine_lap A certain device consumes 28 kW and delivers 14 kW. Find its efficiency.
  14. The ship
    ship_1 The ship went upstream speed of 20 km/h in relation to water. River flows at speed 10 km/h. After half an hour, he stopped and returned downstream to the starting point. How long it took way back when even if downstream speed of ship is 20 km/h in relation
  15. Isosceles trapezoid
    lichobeznik_mo_z8_5 What is the height of an isosceles trapezoid, the base of which has a length of 11 cm and 8 cm and whose legs measure 2.5 cm?
  16. Reduce of the volume
    cubes Calculate how many % reduce the volume of the cube is we reduced length of each edge by 10%.
  17. Stamps and albums
    stamp Michail has in three albums stored 170 stamps. In the first album, there are 14 more than in the second and in the second is by 1/5 less than in the third. How many stamps are in the first album?
  18. CD disc
    CD_disc A compact disc has a diameter of 11.8 cm. What is the surface area of the disc in square centimeters?
  19. Double-track
    vlak_1 On double-track express met with a freight train. Express travel at speed 72 km/h, a freight train at speed 36 km/h. After what time period will be from 9 km apart?
  20. Boots
    vysoke-cizmy Master shoemaker has three apprentices. First do one pair of boots for two days, second for 1 day, third on 1.5 day. If they worked together, for how long it would take made a couple of boots?

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