Combinatorics - math word problems

  1. 2nd class combinations
    color_circle From how many elements you can create 4560 combinations of the second class?
  2. Bits, bytes
    bits Calculate how many different numbers can be encoded in 16-bit binary word?
  3. Party
    party-informatikov At the party everyone clink with everyone. Together, they clink 406 times. How many people were at the party?
  4. Kids
    kids How many different ways can sit 8 boys and 3 girls in line, if girls want to sit on the edge?
  5. Lines
    lines_1 In how many points will intersect 14 different lines, where no two are parallel?
  6. Commitee
    committees A class consists of 6 males and 7 females. How many committees of 7 are possible if the committee must consist of 2 males and 5 females?
  7. Hockey players
    players After we cycle five hockey players sit down. What is the probability that the two best scorers of this crew will sit next to each other?
  8. Lottery
    loteria_1 The lottery is 60000 elk in which 6200 wins. What is the probability that the purchase of 12 elks won nothing?
  9. Monty Hall
    Monty_open_door Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. W
  10. Numbers
    numbers_3 How many different 3 digit natural numbers in which no digit is repeated, can be composed from digits 0,1,2?
  11. Area codes
    us_codes How many 6 digit area codes are possible if the first number can't be zero?
  12. School trip
    hostel_1 The class has 19 students. What different ways students can be accommodated in the hostel, where available 3× 2-bed, 3× 3-bed and 1× 4-bed rooms. (Each room has its unique number)
  13. Toys
    toys 3 children pulled 12 different toys from a box. Many ways can be divided toys so that each children had at least one toy?
  14. Family
    stork_bocian What is the probability that a family with 7 childrens have: exactly 5 girls? 7 girls and 0 boys? Consider the birth probability of a girl is 48.69% and boy 51.31%.
  15. Components
    components In the box are 8 white, 4 blue and 2 red components. What is the probability that we pull one white, one blue and one red component without returning?
  16. Three digits number
    plot How many are three-digit integers such that in they no digit repeats?
  17. Combi-triangle
    komb_triangle On each side of the square is marked 10 different points outside the vertices of the square. How many triangles can be constructed from this set of points, where each vertex of the triangle lie on the other side of the square?
  18. Bulbs
    bulb The probability that the bulb can operate 4000 hours is 0.3. What is the probability that exactly one of eight bulbs can operate 4000 hours?
  19. Cars plates
    car_plate How many different licence plates can country have, given that they use 3 letters followed by 3 digits?
  20. Chess
    sachovnica How many ways can select 4 fields on classic chess board with 64 fields, so that fields don't has the same color?

Do you have an interesting mathematical word problem 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 the e-mail correctly and check whether you don't have a full mailbox.

Please do not submit problems from current active competitions such as Mathematical Olympiad, correspondence seminars etc...



Would you like to compute count of combinations?