Examples for 8th grade - page 7

  1. Division
    bonbons Three siblings Helena, Oliver and George split the bag with candies on merit in the ratio 1:6:3. How many candies should each get if in bag were 210?
  2. Intersections
    intersect_circles How many intersections have circles with radius 12 dm and 17 dm, if the distance of their centers is 20 dm.
  3. Shadow and light
    stin Nine meters height poplar tree has a shadow 16.2 meters long. How long shadow have at the same time Joe if he is 1,4m tall?
  4. Lie/do not lie
    lines_and_points The function is given by the rule f(x) = -x-12. Determine whether point D[-4; 2] lies on this function. Solve graphically or numerically and give reasons for the your answer.
  5. Sphere growth
    sphere How many times grow volume of sphere if radius rises 3×?
  6. Similarity of squares
    squares2_1 The ratio of the similarity of the squares ABCD and KLMN is 2.5. Square KLMN area is greater than area of a square ABCD with side a: ?
  7. Meadow
    ovce-miestami-baran On the meadow grazing horses, cows and sheep, together less than 200. If cows were 45 times more, horses 60 times more and sheep 35 times more than there are now, their numbers would equall. How many horses, cows and sheep are on the meadow together?
  8. Daily average
    weather_forecast Calculate the average temperature during the day, when 14 hours was 20 °C and 10 hours was 15 °C.
  9. Reciprocal
    inverse It is true (prove it) that if a> b> 0: ?
  10. Air mass
    airbaloon What is the weight of the air in a classroom with dimensions 5 m × 2 m × 3.1 m ? The air density is 1.293 kg/m3.
  11. Rhombus HP
    rhombus3_1 Calculate area of the rhombus with height 98 mm and perimeter 20 mm.
  12. Inflation
    tsar Once upon a time, tsar owned a money printer and printed and printed. The result of printing money prices went up,in the first year 5.9 %, in the second 2.4%, in the third 5.9% and in the fourth 5.7%. Then tsar was failed in election. Calculate the av
  13. Lines
    bus Five bus lines runs at intervals 3, 5, 10, 11, 13 minutes. In the morning, suddenly start at 7:00. After how many minutes the bus lines meet again?
  14. MATES
    sazka In MATES (Small Television tipping) from 35 randomly numbers drawn 5 winning numbers. How many possible combinations there is?
  15. Words
    words How many 3 letter "words" are possible using 18 letters of the alphabet? a) n - without repetition b) m - with repetition
  16. Scrap
    chair_bad From 8 products are 2 scrap. What is the probability that the random pick of 2 products have no defective product?
  17. 3y inflation
    bread Price of the bread rise in the first year by 7%, the second year fell by 4% and in the third year increased by 8%. Calculate the average annual increase in price of the bread.
  18. Proof I
    ithinkiam When added to the product of two consecutive integers larger one, we get square larger one. Is this true or not?
  19. Basketball
    friends_1 Peter and Franta threw to the basket. Each had 20 attempts. Peter scored thirteen and twelve Franta. Give them success in percentage.
  20. Two typists
    lasica_typewriter There are two typists who are rewriting the material 705 pages. First can it handle rewrite yourself for 24 days; the second 12 days. First typist wrote material yourself 4 days rest rewrites yourself second typist. How many days will it take rewriting alt

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