Anyone can hep me Permutations and Combinations?

Question

Anxious.

Answer 1

permutations are used when the order is considered.

ex.
given: -person A, person B, person C
-only 2 positions in the company a currently unoccupied.
Pres, and Vice Pres

how many sets are there? 6!
Pres Vice-Pres
A B
A C
B A
B C
C A
C B

combinations are used when the order is not considered.

ex.
given: -person A, person B, person C
-only 2 positions in the board of directors are unoccupied.

how many sets are there? 3!

AB
AC
BC

note: AB = BA because still they both are in the board, so they are classified as only 1. AC=CA, BC=CB

Hope this helps!

Answer 2

permutations: all the different ways of arrange a set of objects.
For instance: in a row of 5 persons, how many ways can thy be arranged. If they are a, b, c, d, e, that means
a, b , c , d, e
a, b, c , e , d
a, b , d, c, e
The general formula for permutations is N ! = N factorial = N * (N-1) * (N-2)*...*1.

In combinations you look to get n objects from a set of m.
In our example, you are asked to select 2 persons from the set of 5, for instance. The general formula is

M!/ (N! * (M-N)!).

In our example 5!/2! 3! = 10