Combinatorics - problems

Would you like to compute count of combinations?

  1. No. of divisors
    triangle_div How many different divisors has number ??
  2. Ace
    ace From complete sets of playing cards (32 cards) we pulled out one card. What is the probability of pulling the ace?
  3. Toys
    toys 3 children pulled 9 different toys from a box. Many ways can be divided toys so that each children had at least one toy?
  4. 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?
  5. Examination
    examination The class is 22 students. How many ways can choose four to examination?
  6. Probabilities
    Venn_diagram If probabilities of A, B and A ∩ B are P (A) = 0.57 P (B) = 0.73 and P (A ∩ B) = 0.12 calculate the following probability (of union. intersect and opposite and its combinations):
  7. Three digits number 2
    numbers_7 Find the number of all three-digit positive integers that can be put together from digits 1,2,3,4 and which are subject to the same time has the following conditions: on one positions is one of the numbers 1,3,4, on the place of hundreds 4 or 2.
  8. The confectionery
    ice_cream The confectionery sold 5 kinds of ice cream. In how many ways can I buy 3 kinds if order of ice creams does not matter?
  9. Ice cream
    zmrzlina Annie likes much ice cream. In the shop are six kinds of ice cream. In how many ways she can buy ice cream to three scoop if each have a different flavor mound and the order of scoops doesn't matter?
  10. Distribution function
    distribution_fcn X 2 3 4 P 0.35 0.35 0.3 The data in this table do I calculate the distribution function F(x) and then probability p(2.5
  11. First class
    prvni_jakost The shipment contains 40 items. 36 are first grade, 4 are defective. How many ways can select 5 items, so that it is no more than one defective?
  12. Two aces
    cards_7 From a 32 card box we randomly pick 1 card and then 2 more cards. What is the probability that last two drawn cards are aces?
  13. Phone numbers
    old_phone How many 9-digit telephone numbers can be compiled from the digits 0,1,2,..,8,9 that no digit is repeated?
  14. Morse alphabet
    morse_code Calculate how many words of Morse code to create compiling commas and dots in the words of one to five characters.
  15. 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?
  16. Dices
    dices_2 We will throw two dice. What is the probability that the ratio between numbers on first and second dice will be 1:2?
  17. Lock
    combination-lock Combination lock will open when the right choice of 5 numbers (from 1 to 12 inclusive) is selected. A. How many different lock combinations are possible? B. Is he combination lock named appropriately?
  18. 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?
  19. Raffle
    tombola_tickets In the pool is numbers from 1 to 135. What is the probability that a randomly selected number is not a prime number?
  20. Bulbs
    bulbs In the box are 18 bulbs with power 60 W, 8 bulbs with power 40 W and 19 with 50 W. Calculate probability that a randomly selected bulb is:

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