Question

You need to have a password with 4
letters followed by 2
even digits between 0
and 9
, inclusive. If the characters and digits cannot be used more than once, how many choices do you have for your password?

Answer 1

There are 26 choices for the first letter of the password, and since each character can only be used once, there are 25 choices for the second letter, 24 choices for the third letter, and 23 choices for the fourth letter.
For the even digits, there are 5 choices (0, 2, 4, 6, 8) for the first digit and 4 choices for the second digit.

Therefore, there are a total of 26 * 25 * 24 * 23 * 5 * 4 = 3,744,000 possible choices for the password.