Examples for 8th grade - page 5

  1. Two cars
    cars_racing Two cars started against each other at the same time to journey long 225 km. First car went 35 km/h and second 48 km/h. What distance will be between this cars 20 minutes before meet?
  2. Circles
    two_circles The areas of the two circles are in the ratio 1:15. The larger circle has diameter 25. Calculate the radius of the smaller circle.
  3. Eiffel Tower
    eiffel_tower Eiffel Tower in Paris is 300 meters high, is made of steel. Its weight is 8000 tons. How tall is the tower model made ​​of the same material, if it weigh is 4.8 kg?
  4. Chickens and rabbits
    pipky In the yard were chickens and rabbits. They had 44 heads and 124 legs. How many chickens and how many rabbits was in the yard?
  5. Widescreen monitor
    lcd Computer business hit by a wave of widescreen monitors and televisions. Calculate the area of ​​the LCD monitor with a diagonal size 37 inches at ratio 4:3 and then 16:9 aspect ratio. Is buying widescreen monitors with same diagonal more advantageous tha
  6. Reverse Pythagorean theorem
    pytagors Given are lengths of the sides of the triangles. Decide which one is rectangular: Δ ABC: 73 m, 66 m, 51 m ? Δ DEF: 63 cm, 105 cm, 84 cm ? Δ GHI: 50 dm, 48 dm, 14 dm ? Δ JKL: 31 m, 45 m, 40 m ? Δ MNO: 28 m, 53 m, 45 m ?
  7. Vinegar 2
    ocet How many percentage of getvinegar solution, if we mix to 14.5 liters of 7.8% and 2.5 liters of 5.8% vinegar?
  8. Tanks
    hasici Fire tank has cuboid shape with a rectangular floor measuring 14.5 m × 9.8 m. Water depth is 2 m. Water was pumped from the tank into barrels with a capacity of 3 hl. How many barrels were used, if the water level in the tank fallen 12 cm? Write
  9. Cylinders
    cylinders Area of the side of two cylinders is same rectangle of 45 cm × 32 cm. Which cylinder has a larger volume and by how much?
  10. Circle arc
    pizza Circle segment has a circumference of 13.26 mm and 252.03 mm2 area. Calculate the radius of the circle and size of central angle.
  11. Ace
    ace From complete sets of playing cards (32 cards) we pulled out one card. What is the probability of pulling the ace?
  12. Square diagonal
    square_d Calculate length of the square diagonal if the perimeter is 200 cm.
  13. Flags
    vlajka_cz How many different flags can be made from colors white, yellow, red, blue, green, orange so that each flag consisted of three different colors?
  14. Numbers
    ten Determine the number of all positive integers less than 2937474 if each is divisible by 11, 23, 17. What is its sum?
  15. MO SK/CZ Z9–I–3
    ball_floating_water John had the ball that rolled into the pool and it swam in the water. Its highest point was 2 cm above the surface. Diameter of circle that marked the water level on the surface of the ball was 8 cm. Determine the diameter of John ball.
  16. Triangle ABC
    triangles_3 Calculate the sides of triangle ABC with area 883 cm2 and if a: b: c = 15:7:19
  17. Ravens
    krkavec The tale of the Seven Ravens were seven brothers, each of whom was born exactly 1.5 years after the previous one. When the eldest of the brothers was 4-times older than the youngest, mother all curse. How old was seven ravens brothers when their mother cur
  18. Time
    time Write time in minutes rounded to one decimal place: 1 h 42 m 22 s.
  19. IS triangle
    isoscelestriangle-pic Calculate interior angles of the isosceles triangle with base 37 cm and legs 36 cm long.
  20. Density - simple example
    mercury Material of density of 1139 kg/m3 occupies a container volume of 83 cm3. What is its mass?

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