Combinatorics - problems

  1. Sweater
    colours_3 Dana confuses sweater and wool has a choice of seven colors. In how many ways she can choose from three colors to the sleeves?
  2. Digit sum
    cisla_7 How many are three-digit numbers that have a digit sum of 6?
  3. The big clock
    hodiny_4 The big clock hands stopped at a random moment. What is the probability that: a) a small hand showed the time between 1:00 and 3:00? b) the big hand was in the same area as a small hand in the role of a)? c) did the hours just show the time between 21:00.
  4. Utopia Island
    doktori A probability of disease A on the island of Utopia is 40%. A probability of occurrence among the men of this island, which make up 60% of all the population (the rest are women), is 50%. What is the probability of occurrence of A disease among women on Uto
  5. Triangles
    triangle_234 Five sticks with a length of 2,3,4,5,6 cm. How many ways can you choose three sticks to form three sides of a triangle?
  6. Blocks
    cubes3_1 There are 9 interactive basic building blocks of an organization. How many two-blocks combinations are there?
  7. Diagonals
    diagonals What x-gon has 54 diagonals?
  8. Three students
    terc2_2 Three students independently try to solve the problem. The first student will solve a similar problem with a probability of 0.6, the second student will solve at a probability of 0.55, and the third will solve at a probability 0.04. The problem is resolved
  9. Dice
    dices2_5 We throw 10 times a play dice, what is the probability that the six will fall exactly 4 times?
  10. No. of divisors
    triangle_div How many different divisors has number ??
  11. Rectangle
    diagonal In rectangle with sides 3 and 10 mark the diagonal. What is the probability that a randomly selected point within the rectangle is closer to the diagonal than to any side of the rectangle?
  12. 7 heroes
    7statocnych 5 heroes galloping on 5 horses behind. How many ways can sort them behind?
  13. Ace
    ace From complete sets of playing cards (32 cards) we pulled out one card. What is the probability of pulling the ace?
  14. Flags
    vlajka_cz How many different flags can be made from colors purple, yellow, red, white, blue, green, orange so that each flag consisted of three different colors?
  15. Vans
    shuttlevan In how many ways can 5 shuttle vans line up at the airport?
  16. Seating
    kupe_1 How many ways can 7 people sit on 2 numbered chairs (eg seat reservation on the train)?
  17. Pediatrician
    doctor Pediatrician this month of 21 working days takes 3 days holidays. What is the probability that on Monday will be at work?
  18. Bureau of Labor
    UPSVAR Bureau of Labor is a state institution that provides mike and the rest for their so-called clients. The mission of the Bureau of Labor is spend taxpayer money to provide relaxation and benefits to those who do not want to work. Popularly speaking sense the
  19. Guests
    hostia How many ways can 8 guests sit down on 10 seats standing in a row?
  20. 2nd class variations
    cards From how many elements you can create 6972 variations of the second class?

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