Examples for 8th grade - page 7

  1. Sea water
    sea_1 Seawater contains about 4.7% salt. How many dm3 of distilled water we must pour into 39 dm3 of sea water to get water with 1.5% salt?
  2. Present
    prezent Gift box has rectangular shape with dimensions of 8×8×3 cm. Miloslav wants to cover with square paper with sides of 18 cm. How much paper left him?
  3. Road repair
    workers_1 Road repair took 10 days for 36 workers if they worked 9 hours a day. How many days take repair same road 37 workers if they work 8 per day?
  4. Engineer Kažimír
    demagog_smer_1 The difference between politicians-demagogues and reasonable person with at least primary education beautifully illustrated by the TV show example. "Engineer" Kažimír says that during their tenure there was a large decline in the price of natural gas, pri
  5. Rectangle
    golden-rectangle-ratio Calculate the length of the side GN and diagonal QN of rectangle QGNH when given: |HN| = 25 cm and angle ∠ QGH = 28 degrees.
  6. Gear
    ozubene_kolesa Two gears, fit into each other, has transfer 2:3. Centres of gears are spaced 82 cm. What are the radii of the gears?
  7. Tare
    camion Gross weight of shipment is 5188 kg and its tare is 5.6%. Calculate the net weight of the shipment.
  8. Car
    american-cars Car goes from point A to point B at speed 86 km/h and back 53 km/h. If they goes there and back at speed 67 km/h trip would take 10 minutes shorter. What is distance between points A and B?
  9. Motion
    cycling Cyclist started at 9:00 from point S to point T. After 10 minutes, followed him at the same speed the second cyclist. Walker, which went from T to S, started at 9:35. After 71 minutes he met the first cyclist and after next 8 minutes the second cyclist. Di
  10. Barrel of oil
    dieselbarrel Barrel of oil weighs 283 kg. When it mold 26% oil, weighed 216 kg. What is the mass of the empty barrel?
  11. Isosceles right triangle
    3triangles Calculate the area of an isosceles right triangle whose perimeter is 377 cm.
  12. Maximum area of rhombus
    rhombus Calculate the interior angles at which equilateral rhombus has maximum area.
  13. Pediatrician
    doctor Pediatrician this month of 21 working days takes 3 days holidays. What is the probability that on Monday will be at work?
  14. Rhombus and inscribed circle
    rhombus_2 It is given a rhombus with side a = 75 cm and the radius of the inscribed circle r = 36 cm. Calculate the length of its two diagonals.
  15. Rectangle
    rectangle_ABCD In rectangle ABCD with sides |AB|=19, |AD|=16 is from point A guided perpendicular to the diagonal BD, which intersects at point P. Determine the ratio ?.
  16. Cone
    cones Circular cone of height 15 cm and volume 5699 cm3 is at one-third of the height (measured from the bottom) cut by a plane parallel to the base. Calculate the radius and circumference of the circular cut.
  17. Rectangle - sides ratio
    rectangle_2 Calculate area of rectangle whose sides are in ratio 3:13 and perimeter is 673.
  18. Cube zoom
    krychle_1 How many percent we increase volume and surface of cube, if we magnify its edge by 38%.
  19. Expansion
    magnification If one side of the rectangle is larger 4-times and second 2-times, what percentage increases the area of rectangle?
  20. Radians
    pi_text Convert 270° to radians. Write result as multiple of number π.

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