Permutation Formula
A formula for the number of possible
permutations of k objects from a set of n. This is
usually written _{n}P_{k} .
Formula: 

Example: 
How many ways can 4 students from a group of 15 be lined up for a photograph? 
Answer: 
There are _{15}P_{4} possible permutations of 4 students from a group of 15.
different lineups 
See
also
Combination
formula, factorial
