Examples for 8th grade - page 58

  1. Ethnicity
    indian Share of ethnicity XY is 10%, which is 1/9 more than in the prewar period. What was the share of that ethnicity in the pre-war period?
  2. Square circles
    stvorec_kruh Calculate the length of the described and inscribed circle to the square ABCD with a side of 5cm.
  3. Wheel diameter
    koleso_1 A 1m diameter wheel rolled along a 100m long track. How many times did it turn?
  4. Percent chaining
    meter_1 Calculate 20% from 70% from 80 km
  5. Work at plant
    workers_4 Handyman has vowed to do repair work at the plant for 25 days. However, work had to be shortened and therefore gained helper. Together they made all the corrections for 13 1/3 days. How long the work would take helper himself?
  6. School year
    boys_girls At the end of the school year has awarded 20% of the 250 children who attend school. Awat got 18% boys and 23% of girls. Determine how many boys and how many girls attend school.
  7. The chord
    circles_4 Calculate a chord length which the distance from the center of the circle (S, 20 cm) equals 7 cm.
  8. Pyramid in cube
    pyramid_in_cube In a cube with edge 12 dm long we have inscribed pyramid with the apex at the center of the upper wall of the cube. Calculate the volume and surface area of the pyramid.
  9. Football league
    football_3 In the football league is 16 teams. How many different sequence of results may occur at the end of the competition?
  10. Coal
    coal If the daily consumption of 1.6 tons of coal, it is sufficient to supply the boiler for 42 days. How long is sufficient to supply when will burn only 1.2 tons of coal a day ?
  11. Typing course
    typewriter_1 Before taking a typing course, Seth could type 30 words per minute. By the end of the course, he was able to type 66 words per minute. Find the percent increase.
  12. Hexa prism
    hexagon Determine the volume of hex prism with edge base 4 cm. The body height is 28 cm.
  13. Painters
    maliri 15 painters painted fence for 280 minutes. For how many minutes paint half of this fence 12 painters?
  14. Uranium ore
    uran Uranium ore contains 0.2% of pure uranium and pure uranium contains 0.07% of fissile uranium. How many grams of fissile uranium contains 2200 ton of uranium ore?
  15. 4 pipes
    roury The tank flows out by 4 pipes in 6 hours 120 hl water. How much water flows out of 5 pipes of the same diameter in 14 hours?
  16. The book
    1438931371257-1350799500 If one day you read p pages, you will read the book 24 days. If you read each day 10 pages more, you would read a book in 16 days. How many pages have the book?
  17. Grid/network of cube
    siet_kocky Grid of cube has a circumference 42 mm. Calculate the surface area of the cube ...
  18. Lift
    lanovka_2 The largest angle at which the lift rises is 16°31'. Give climb angle in permille.
  19. Pupils at cinema
    tickets_1 Alena bought movie tickets for two groups of pupils. The first group purchased 7 tickets for 1st and 5 tickets for 2nd place and she pay 62Kč. For the second group bought 11 tickets for 1st and 4 tickets for 2nd place and pay 82Kč. How much was the ticket
  20. Similarity
    podobnost ABC is a triangle wherein a = 4 cm, b = 6 cm, c = 8 cm. Is it similar to the triangle DEF: d = 3 cm, e = 4.5 cm, f = 6 cm? If so, determine the ratio of similarity.

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