Combinatorics - problems

Would you like to compute count of combinations?

  1. Word
    words What is the probability that a random word composed of chars T, I, O, D, I will be IDIOT?
  2. Football league
    football In the 2nd football league is 19 teams. How many ways can be filled first, second and third place?
  3. Events
    items Event J has probability of 0.17. What is the probability that the event J occurs in:
  4. Kids
    kids How many different ways can sit 5 boys and 5 girls in line, if girls want to sit on the edge?
  5. Seating rules
    school_class In a class are 22 seats but in 2.B class are only 14 students. How many ways can student seat? (The class has 11 benches. A bench is for a pair of students.) Result (large number) logarithm and thus write down as powers of 10.
  6. The dice
    hracia-kocka What is the probability of events that if we throw a dice is rolled less than 6?
  7. Combinations
    circles.GIF How many different combinations of two-digit number divisible by 4 arises from the digits 3, 5 and 7?
  8. 7 heroes
    7statocnych 5 heroes galloping on 5 horses behind. How many ways can sort them behind?
  9. 2nd class variations
    cards From how many elements you can create 6480 variations of the second class?
  10. Two doctors
    dr_cvach Doctor A will determine the correct diagnosis with a probability 80% and doctor B with a probability 72%. Calculate probability of correct diagnosis if patient is diagnosed by both doctors.
  11. Playing cards
    playing_cards How many possible ways are to shuffle 7 playing cards?
  12. Pizza
    pizza_1 A school survey found that 9 out of 16 students like pizza. If 5 students are chosen at random, what is the probability that all 5 students like pizza?
  13. Area codes
    us_codes How many 6 digit area codes are possible if the first number can't be zero?
  14. Cars plates
    car_plate How many different licence plates can country have, given that they use 3 letters followed by 4 digits?
  15. Count of triangles
    SquareTriangle Given a square ABCD and on each side 8 internal points. Determine the number of triangles with vertices at these points.
  16. Combinatorics
    fontains The city has 7 fountains. Works only 6. How many options are there that can squirt ?
  17. Chess
    chess How many different ways can initiate a game of chess (first pass)?
  18. Medicine
    lieky We test medicine on 6 patients. For all drug doesn't work. If the drug success rate of 20%, what is the probability that medicine does not work?
  19. Neighborhood
    glasses_1 I have 7 cups: 1 2 3 4 5 6 7. How many opportunities of standings cups are there if 1 and 2 are always neighborhood?
  20. Five-digit
    cards Find all five-digit numbers that can be created from numbers 12345 so that the numbers are not repeated and then numbers with repeated digits. Give the calculation.

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