A 6-character password is to be formed from the following characters.

Letters: c, h, p, r, t

Numbers: 2, 4, 6, 8

Symbols: \$, ?, \&

Each character can be used at most once in any 6-character password.

(a) Find the number of 6-character passwords that can be formed if there are no further restrictions.

(b) Find the number of 6-character passwords that can be formed if the password starts and ends with a number.

(c) Find the number of 6-character passwords that can be formed if the password:

• starts with either a letter and then a symbol, or a symbol and then a letter

• ends with 2 numbers.

Permutations and Combinations - Worked Solutions