A processing program requires a user to enter a 6-digit registration code made up of the digits 1, 2, 3, 4, 5, 6, 7, 8 and 9. No digit can be used more than once.

Answer 1

Is the question something like "How many possible registration codes are there?" If so,this is asking what is the number of possible sets of 9 numbers taken 6 at a time where order makes a difference. To find the answer, use the permutation function in your calculator bu typing ₉P₆ into your calculator. If your calculator doesn't have the permutation formula built into it, use the permutation equation _nP_r = n!/(n - r)! or ₉P₆ = 9!/(9-6)! = 60,480