Combinatorial number - examples

See also our combinations calculator.

  1. Test
    test_4 The teacher prepared a test with ten questions. The student has the option to choose one correct answer from the four (A, B, C, D). The student did not get a written exam at all. What is the probability that: a) He answers half correctly. b) He answers.
  2. Word
    words What is the probability that a random word composed of chars M, R, P, E, I, O, G, S, S, G, R, T, E, C, E, N, I, O, O, R will be GEOMETRICPROGRESSION?
  3. Chocolates
    Chocolate In the market have 3 kinds of chocolates. How many ways can we buy 13 chocolates?
  4. Rectangles
    rectangles How many rectangles with area 2832 cm2 whose sides is natural numbers are?
  5. Sales
    tesco From statistics of sales goods, item A buy 54% of people and item B buys 58% of people. What is the probability that from 3 people buy 2 item A and 1 item B?
  6. Stacks
    euro_stacks Annie has a total of $ 969. The money must be divided into stacks so that each buyer has the same amounth of dollars. How many options she have?
  7. Candy
    bulls How many ways can divide 22 identical candies to 4 children?
  8. N-gon
    ngon How many diagonals has convex 29-gon?
  9. Pairs
    dvojice From the five girls and four boys teachers have to choose one pair of boy and girl. A) How many such pairs of (M + F)? B) How many pairs where only boys (M + M)? C) How many are all possible pairs?
  10. Party
    party-informatikov At party overyone clink with everyone. Together, they clink 406 times. How many people were at the party?
  11. 2nd class combinations
    color_circle From how many elements you can create 1081 combinations of the second class?
  12. Lines
    lines_1 In how many points will intersect 11 different lines, where no two are parallel?
  13. Commitee
    committees A class consists of 12 males and 19 females. How many committees of 4 are possible if the committee must consist of 2 males and 2 females?
  14. Family
    stork_bocian What is the probability that a family with 7 childrens have: exactly 0 girls? 1 girl and 6 boys? Consider the birth probability of a girl is 48.73% and boy 51.27%.
  15. Bulbs
    bulb The probability that the bulb can operate 4000 hours is 0.13. What is the probability that exactly one of eight bulbs can operate 4000 hours?
  16. Examination
    examination The class is 22 students. How many ways can choose four to examination?
  17. Math logic
    children_7 There are 20 children in the group, each two children have a different name. Alena and John are among them. How many ways can we choose 8 children to be among the selected A) was John B) was John and Alena C) at least one was Alena, John D) maximum one w
  18. Tournament
    turnaj Determine how many ways can be chosen four representatives from 27 students to school tournament.
  19. The camp
    diary At the end of the camp a 9 friends exchanged addresses. Any friend gave remaining 8 friends his card. How many addresses they exchanged?
  20. Circles
    circles How many different circles is determined by 12 points at the plane, if 7 of them lie in a straight line?

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