Examples for 8th grade - page 7

  1. 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: ?
  2. Words
    words How many 3 letter "words" are possible using 18 letters of the alphabet? a) n - without repetition b) m - with repetition
  3. 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
  4. 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?
  5. Copiers
    images Three copiers will do the same in an hour k copies. How many copies would be done in an hour by four such copiers? ?
  6. Scrap
    chair_bad From 8 products are 2 scrap. What is the probability that the random pick of 2 products have no defective product?
  7. MATES
    sazka In MATES (Small Television tipping) from 35 randomly numbers drawn 5 winning numbers. How many possible combinations there is?
  8. Proof I
    ithinkiam When added to the product of two consecutive integers larger one, we get square larger one. Is this true or not?
  9. 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.
  10. Octahedron - sum
    8sten On each wall of a regular octahedron is written one of the numbers 1, 2, 3, 4, 5, 6, 7 and 8, wherein on different sides are different numbers. For each wall John make the sum of the numbers written of three adjacent walls. Thus got eight sums, which also.
  11. Three digits number
    plot How many are three-digit integers such that in they no digit repeats?
  12. Divisors
    divisors The sum of all divisors unknown odd number is 1482. Determine sum of all divisors of number which is twice of unknown numbers.
  13. Barrel of oil
    dieselbarrel Barrel of oil weighs 282 kg. When it mold 56% oil, weighed 138 kg. What is the mass of the empty barrel?
  14. Forestry workers
    forestry_workers In the forest is employed 63 laborers planting trees in nurseries. For 11 hour work day would end job in 43 days. After 14 days, 22 laborers go forth. How many days is needed to complete a planting trees in nurseries by others, if they will work 15 hours
  15. 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?
  16. Root
    sq_root Use law of square roots roots: ?
  17. Lock
    combination-lock Combination lock will open when the right choice of 5 numbers (from 1 to 12 inclusive) is selected. A. How many different lock combinations are possible? B. Is he combination lock named appropriately?
  18. Height 2
    1unilateral_triangle Calculate the height of the equilateral triangle with side 43.
  19. Mine
    minetower Wheel in traction tower has a diameter 5 m. How many meters will perform an elevator cabin if wheel rotates in the same direction 10 times?
  20. Store
    pave One meter of the textile were discounted by 2.4 USD. Now 6 m of textile cost as before 3 m. Calculate the old and new price of 1 m of the textile.

Do you have interesting mathematical example that you can't solve it? Enter it and we can try to solve it.

To this e-mail address we will reply solution; solved examples are also published here. Please enter e-mail correctly and check whether you don't have a full mailbox.