2.13: 5-digit codes from mixed character sets
A 5-digit code is formed using the following characters.
Letters: a, e, i, o, u
Numbers: 1, 2, 3, 4, 5, 6
Symbols: @, *, #
No character can be repeated in a code.
(i)[2]
Find the number of possible codes if there are no restrictions.
(ii)[2]
Find the number of possible codes if the code starts with a symbol followed by two letters and then two numbers.
(iii)[2]
Find the number of possible codes if the first two characters are numbers, and no other numbers appear in the code.