Examples for 9th grade - page 7

  1. 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.
  2. Three digits number
    plot How many are three-digit integers such that in they no digit repeats?
  3. 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.
  4. 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?
  5. Lines
    lines_1 In how many points will intersect 11 different lines, where no two are parallel?
  6. Root
    sq_root Use law of square roots roots: ?
  7. Dice
    dices How many times must throw the dice, the probability of throwing at least one three was greater than 90%?
  8. 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?
  9. Machine
    machine Price of the new machine is € 56000. Every year is depreciated 16% of residual value. What will be the value of the machine after 5 years?
  10. 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.
  11. Morse alphabet
    morse_code Calculate how many words of Morse code to create compiling commas and dots in the words of one to five characters.
  12. 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?
  13. 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.
  14. Salary
    500euro Clerk got to pay 1200 Euros in banknotes of 50 and 200 Eur. Total got 9 banknotes. How many was which?
  15. Party
    party-informatikov At party overyone clink with everyone. Together, they clink 406 times. How many people were at the party?
  16. Tanker
    oil-tanker An oil tanker can be emptied by the first pump in 4.4 hours. Second pump can empty an tanker in 7.8 hours. If the first pump started at 8:00 and second 1.4 hour later, at what time will the tanker be empty?
  17. Circles
    three-circles Three circles of radius 71 cm 76 cm and 22 cm is mutually tangent. What is the perimeter of the triangle whose vertices are centers of the circles?
  18. 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
  19. Server
    p_pro Calculate how many average minutes a year is the web server is unavailable, the availability is 99.99%.
  20. Road - permille
    18procent 5 km long road begins at an altitude 500 meters above sea level and ends at a altitude 521 ASL. How many permille road rises?

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