Question

Students log onto a university’s virtual campus with a user name consisting of eight characters: four uppercase letters of the alphabet followed by four digits.

(a) How many user names are theoretically possible for this system?

(b) How many user names have no repeated letters or digits?

(c) How many user names begin with A and end with 9?

(d) How many user names cannot begin with a vowel and must end with a number greater than or equal to 3 and less than or equal to 7?

Answer 1