Combinatorics - examples - page 7

  1. Combinations
    circles How many different combinations of two-digit number divisible by 4 arises from the digits 3, 5 and 7?
  2. Trinity
    trojka How many different triads can be selected from the group 43 students?
  3. Sum on dice
    dices2 We have two dice. What is the greater likelihood of fall a total sum 7 or 8 ? (write 7, 8 or 0 if the probabilities are the same)?
  4. 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?
  5. Probability - tickets
    zreby What is the probability that when you have 25 tickets in 5000 that you wins the first (one) prize?
  6. Throw
    dices6_1 We throw 2 times with 2 dices. What is the probability that the first roll will fall more than sum of 9 and the second throw have sum 3 or does not have the sum 4?
  7. Class - boys and girls
    kresba In the class are 60% boys and 40% girls. Long hair has 10% boys and 80% girls. a) What is the probability that a randomly chosen person has long hair? b) The selected person has long hair. What is the probability that it is a girl?
  8. Salami
    salama How many ways can we choose 5 pcs of salami, if we have 6 types of salami for 10 pieces and one type for 4 pieces?
  9. Confectionery
    cukrovinky The village markets have 5 kinds of sweets, one weighs 31 grams. How many different ways a customer can buy 1.519 kg sweets.
  10. 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.
  11. Task of the year
    years Determine the number of integers from 1 to 106 with ending four digits 2006.
  12. Four swords
    fight Obelix has three helmets, four swords and five shields. How many swords must make at the blacksmith forge Metallurgix to be able to walk another 90 days in unique armor?
  13. Normal Distribution
    normal_d At one college, GPA's are normally distributed with a mean of 3.1 and a standard deviation of 0.4. What percentage of students at the college have a GPA between 2.7 and 3.5?
  14. Lines
    lines_4 How many lines can be draw with 8 points, if three points lie on one line and the other any three points do not lie on the same line?
  15. Variations
    pantagram Determine the number of items when the count of variations of fourth class without repeating is 42 times larger than the count of variations of third class without repetition.
  16. Doctor 2
    heart A doctor noted the Diastolic Blood Pressure (DBP) of a large number of patients. Later, he scrambled the data to keep the privacy of his patients. Based on the scrambled dataset, he finds that the lower inner fence is equal to 50 and the upper inner fenc
  17. Sum 10
    dices11 What is the probability that two dice throw twice in a row will result the sum of 10?
  18. Fish tank
    zebra_fish A fish tank at a pet store has 8 zebra fish. In how many different ways can George choose 2 zebra fish to buy?
  19. 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.
  20. Lottery
    lottery Fernando has two lottery tickets each from other lottery. In the first is 973 000 lottery tickets from them wins 687 000, the second has 1425 000 lottery tickets from them wins 1425 000 tickets. What is the probability that at least one Fernando's ticket w

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