Introduction to Probability

Introduction to Probability

Permutations

It is a way of ordering a group of objects in such a way that ordering is of importance. eg: Find all possible ways in which 10 people can be seated in 10 seats.

If "n" objects are to be placed in "r" available spaces, then the number of ways this can be acheived is given by:  

nPr = (n)! / (n - r)!