Multiplication + multiplication principle - examples

  1. No. of divisors
    triangle_div How many different divisors has number ??
  2. 7 heroes
    7statocnych 5 heroes galloping on 5 horses behind. How many ways can sort them behind?
  3. Flags
    vlajka_cz How many different flags can be made from colors white, yellow, red, blue, green, orange so that each flag consisted of three different colors?
  4. Vans
    shuttlevan In how many ways can 7 shuttle vans line up at the airport?
  5. Seating
    kupe_1 How many ways can 7 people sit on 3 numbered chairs (eg seat reservation on the train)?
  6. Guests
    hostia How many ways can 7 guests sit down on 9 seats standing in a row?
  7. Shelf
    bookshelf.JPG How many ways are there to arrange 9 books on a shelf?
  8. 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?
  9. Football league
    football In the 2nd football league is 19 teams. How many ways can be filled first, second and third place?
  10. 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.
  11. Pairs
    pair At the table sit 12 people, 6 on one side and 6 on the other side. Among them are 5 pairs. Every pair wants to sit opposite each other. How many ways can they sit?
  12. Coin and die
    die Flip a coin and then roll a six-sided die. How many possible combinations are there?
  13. Candy
    bulls How many ways can divide 22 identical candies to 4 children?
  14. Lock
    combination-lock Combination lock will open when the right choice of 4 numbers (from 1 to 14 inclusive) is selected. A. How many different lock combinations are possible? B. Is he combination lock named appropriately?
  15. Bits, bytes
    bits Calculate how many different numbers can be encoded in 16-bit binary word?
  16. Pairs
    dvojice From the five girls and four boys teachers have to choose one pair of boy and girl. A) How many such pairs of (M + F)? B) How many pairs where only boys (M + M)? C) How many are all possible pairs?
  17. Kids
    kids How many different ways can sit 5 boys and 5 girls in line, if girls want to sit on the edge?
  18. Commitee
    committees A class consists of 12 males and 19 females. How many committees of 4 are possible if the committee must consist of 2 males and 2 females?
  19. School trip
    hostel_1 Class has 21 students. What different ways students can be accommodated in the hostel, where available 2× 2-bed, 3× 3-bed and 2× 4-bed rooms. (Each room has its own unique number)
  20. Three digits number
    plot How many are three-digit integers such that in they no digit repeats?

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