Annabelle's password is a 3-digit code that uses the numbers 0, 1, and 2. How many possible outcomes are there for Annabelle's password if the digits can repeat?

27

9

21

3

You have 8 choices for the third digit (digits 0 - 9 excluding the numbers you chose for the first and second digit). So by the multiplication principle (MP), there are 9*9*8 ways to do this. So there are 648 numbers that are 3 digit numbers and have no repeated digits.

Answer: The answer is 27