Overview
What is the main difference between a permutation and a combination? Give an example for both
2) A system designer is asked to design an inventory system for a hardware manufacturer. The system designer must decide a way to identify the different kinds of hardware. Each four-digit id # is to begin with two letters of the alphabet. Any letter can be used except I, O and Z. The rest of the id # is to consist of digits 0-1. How many such unique id #s can the designer make?