Combinations

Combinations is defined as a selection of objects in which order is not important.

There are two formuls that I was able to finsd for calculating this; the first being as read:

n= total
r = want
! = factorial
Another way to find the nuber of combinations possible is as follows:

-First use the fundamental counting principle and then divide the number by the number of ways in which the "objects" can be arranged.

Since this is new to all of this and we're trying to help one another learn I decided to add in an example question from an old textbook.

Example

How many different pairs of cards can be chosen from the 5 cards in a royal flush?By using the fundamental counting principle, there are 5 x 4 ways to choose the cards in order. The number of ways in which 2 cards can be arranged is 2! = 2 x 1. Therefore, the number of pairs of cards that can be chosen is:

5 x 4 / 2 x 1 = 20 / 2 = 10

Unfortunately there isn't much more I can do or say as this is s new to me as anyone else. I look forward to seeing what other classmates have found and enjoyed this new way of learning