Multiplication + multiplication principle - examples
- No. of divisors
How many different divisors has number ??
- 7 heroes
5 heroes galloping on 5 horses behind. How many ways can sort them behind?
How many different flags can be made from colors white, yellow, red, blue, green, orange so that each flag consisted of three different colors?
In how many ways can 7 shuttle vans line up at the airport?
How many ways can 7 people sit on 3 numbered chairs (eg seat reservation on the train)?
How many ways can 7 guests sit down on 9 seats standing in a row?
How many ways are there to arrange 9 books on a shelf?
- Phone numbers
How many 9-digit telephone numbers can be compiled from the digits 0,1,2,..,8,9 that no digit is repeated?
- Football league
In the 2nd football league is 19 teams. How many ways can be filled first, second and third place?
- Morse alphabet
Calculate how many words of Morse code to create compiling commas and dots in the words of one to five characters.
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?
- Coin and die
Flip a coin and then roll a six-sided die. How many possible combinations are there?
How many ways can divide 22 identical candies to 4 children?
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?
- Bits, bytes
Calculate how many different numbers can be encoded in 16-bit binary word?
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?
How many different ways can sit 5 boys and 5 girls in line, if girls want to sit on the edge?
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?
- School trip
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)
- Three digits number
How many are three-digit integers such that in they no digit repeats?