High school + combinatorial number - examples - page 4

  1. Dice
    dices2_5 We throw 10 times a play dice, what is the probability that the six will fall exactly 4 times?
  2. Classroom
    ziaci_7 Of the 26 pupils in the classroom, 12 boys and 14 girls, four representatives are picked to the odds of being: a) all the girls b) three girls and one boy c) there will be at least two boys
  3. Families 2
    family_24 There are 729 families having 6 children each. The probability of a girl is 1/3 and the probability of a boy is 2/3. Find the the number of families having 2 girls and 4 boys.
  4. 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.
  5. Raffle
    tombola_3 There are 200 draws in the raffle, but only 20 of them win. What is the probability of at least 4 winnings for a group of people who have bought 5 tickets together?
  6. 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
  7. Boys and girls
    dices2_10 There are 11 boys and 18 girls in the classroom. Three pupils will answer. What is the probability that two boys will be among them?
  8. Diagonals
    diagonals_1 What x-gon has 54 diagonals?
  9. A pizza
    pizza_11 A pizza place offers 14 different toppings. How many different three topping pizzas can you order?
  10. Family
    family_32 94 boys are born per 100 girls. Determine the probability that there are two boys in a randomly selected family with three children.
  11. A book
    books_32 A book contains 524 pages. If it is known that a person will select any one page between the pages numbered 125 and 384, find the probability of choosing the page numbered 252 or 253.
  12. Combinations 6
    dices2_3 6 purses 9 flaps 12 straps Every combination must include 1 purse, 1 flap and 1 strap. How many possible combinations?
  13. Three workplaces
    workers_49 How many ways can we divide nine workers into three workplaces if they need four workers in the first workplace, 3 in the second workplace and 2 in the third?
  14. Peaches
    broskve There are 20 peaches in the pocket. 3 peaches are rotten. What is the probability that one of the randomly picked two peaches will be just one rotten?
  15. Subsets
    venn5 How many 19 element's subsets can be made from the 26 element set?
  16. Bridge cards
    cards2 How many bridge hands are possible containing 4 spades,6 diamonds, 1 club, and 2 hearts?
  17. Cancel fractions
    zlomky_15 Compress the expression of factorial: (n+6)!/(n+4)!-n!/(n-2)!
  18. Menu
    jedalnicek On the menu are 12 kinds of meal. How many ways can we choose four different meals into the daily menu?
  19. Three numbers
    dices2_9 We have three different non-zero digits. We will create all 3 digits numbers from them to use all 3 figures in each number. We add all the created numbers, and we get the sum of 1554. What were the numbers?
  20. STRESSED word
    DESSERTS Each letter in STRESSED is printed on identical cards, one letter per card and assembled in random order. Calculate the probability that the cards spell DESSERTS when assembled.

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