Reason - 9th grade (14y) - examples

  1. Two sisters
    cd_disc Two sisters together have 54 CDs. 6/8 CDs has younger sister and is equal to 3/5 of CDs older sisters. How many CDs has each of the sisters?
  2. Brick wall
    plot_zed Garden 70 m long and 48 m wide should surround with wall 2.1 meters high and 30 cm thick. How many we will need bricks if to 1 m³ is needed approximately 300 bricks?
  3. Pyramid Z8–I–6
    pyramida_mo Each brick of pyramid contains one number. Whenever possible, the number in each brick is lowest common multiple of two numbers of bricks lying directly above it. That number may be in the lowest brick? Determine all possibilities.
  4. Troops
    regiment Route is long 203 km and the first day first regiment went at an average speed 20 km/h and journey back 19 km/h. The second day went second regiment same route at an average speed 18 km/h there and back. Which regiment will take route longer?
  5. Seating
    kupe_1 How many ways can 7 people sit on 3 numbered chairs (eg seat reservation on the train)?
  6. Stock market
    money_1 Simon one day decided to invest € 48000 to the stock market. After six months he invested July 11 stock markets fell by 43%. Fortunately for Simon from July 11 5 to October 11 his shares have risen by 13%. Simon is then: ?
  7. Candies
    bonbons_2 In the box are 12 candies that look the same. Three of them are filled with nougat, five by nuts, four by cream. At least how many candies must Ivan choose to satisfy itself that the selection of two with the same filling? ?
  8. Logic
    blue-barrel A man drinks a barrel of water for 31 days, woman for 58 days, for how many days they drink barrel together?
  9. Series
    posloupnost_an Andrew wrote this series of numbers: 1,3,7,15, .... n. Which number in the series does not belong? ?
  10. Lord Ram
    sheep When lord Ram founded the breed white sheep was 8 more than black. Currently white sheep are four times higher than at the beginning and black three times more than at the beginning. White sheep is now 42 more than the black. How many white and black sh
  11. Tractors
    tractors Fields go plow two tractors with various performance. The first tractor plow whole field in 5 hours, the second tractor plow whole field 5 hours longer. How long take plow whole field with two tractors?
  12. Monkey
    monkey Monkey fell in 31 m deep well. Every day her scramble 3 meters, at night dropped back by 2 m. On that day it gets hangover from the well?
  13. Team
    football The football team has 11 players. Their average age is 21 years. During the match due to injury, one player withdraws and the average age of the team is 20. How old was injured player?
  14. Sequence
    arithmetic_seq In the arithmetic sequence is a1=-9, d=4. Which member is equal to the number 147?
  15. Z9-I-4
    numbers_30 Kate thought a five-digit integer. She wrote the sum of this number and its half at the first line to the workbook. On the second line wrote a total of this number and its one fifth. On the third row she wrote a sum of this number and its one nines. Fi
  16. Bonus
    moeny Gross wage was 1113 USD including 16% bonus. How many USD were bonuses?
  17. Tunnels
    Mysky Mice had built an underground house consisting of chambers and tunnels: • each tunnel leading from the chamber to the chamber (none is blind) • from each chamber lead just three tunnels into three distinct chambers, • from each chamber mice can get to any
  18. Shooter
    terc The probability that a good shooter hits the center of the target circle I is 0.22. The probability that the target hit intercircle is II 0.41. What is the probability that it hits the target circle I or II?
  19. Two workers
    Frog Two workers together execute some work in 10 days. The first worker would have done himself in 20 days. How many days would have done himself a second worker?
  20. Accidents
    nehoda-pomnik The count of accidents in 1993 caused 8009 women which is 7.1%. How many men caused the accidents?

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.