What is Permutations and combinations?

Permutations and combinations

Permutations-In math, permutations are related to the act of arranging all the members of a set into some sequence or order. In other words, we can say if the set is already ordered, then the rearranging of its elements is called the permuting process. It occurs, in more or less prominent ways, in almost every area of math. They often arise when different orderings on certain finite sets are considered.

Example of permutations- we have three letters A, B,C . In order to group these letters together , we can do it in the following way - ABC,ACB,BCA,CBA,CAB,BAC.

Combination- it is a way of selection of items from a collection , such that the

the order of selection does not matter. In small cases, it is possible to count the number of combinations. It refers to the combination of n things taken k at a time without repetition.

Example of combination- from a team of three members Anu , Raj, Adi we have to select two members. The possibilities are- Anu and Raj, Anu and Adi, Raj and Adi Permutations formula- It is the choice of r things from a set of n things without replacement and where the order matters.

Combination formula

It is the choice of r things from a set of n things without replacement and where order doesn't matter.