Permutations: They are problems in which ORDER MATTERS to find a solution. Here is the formula: With repetition: N^r Without: n! / ( n – r )! Examples: Combination lock (with repeats) and pool game (without repeats)
Combinations: They are problems in which ORDER DOESN’T MATTER. The formula is:
Without Repeats: n! / r! (n – r)!
With Repeats: (n + r – 1)! / r! (n – 1)!
Sorry, but I couldn’t find examples for the combinations