Passwords on an ancient computer are required to be 4-5 characters long and made up of...

90.2K

Verified Solution

Question

Advance Math

Passwords on an ancient computer are required to be 4-5characters long and made up of lower case letters only (a..z :there are 26 possibilities). Please answer each of these questionsbelow, giving numerical answers. You should also explain how yougot each answer, for full or partial credit.
a) Assume that letters may NOT be repeated, and passwords are4-5 letters long. How many passwords are possible?
b) Assume that letters MAY be repeated, and passwords are 4-5letters long. How many passwords are possible?
c) Assuming that letters MAY be repeated, what proportion of thetotal number of passwords in fact do have at least one letterused more than once?
d) Letters may be repeated but the following extra rulesexist:
The password cannot be 4 or 5 identical letters like xxxx orbbbbb
The password cannot be on a list of 71 common 4-5 letter words(none of them are like xxxx or bbbbb!)
How many passwords are possible now?
Note: since this is a practice test question, the answers can beseen in the question comment after you turn in your quiz. Canvascan't grade \"essay\" type questions for correctness, so you will geta 0 grade whatever you write.

Answer & Explanation Solved by verified expert

4.1 Ratings (585 Votes)

a Case1 Password is four letters long The first letter has 26 choices The second letter has 25 choices since the letters cannot be repeated Similarly the third letter has 24 choices and the fourth letter has 23 choices Total number of password possible in this case26252423358800 Case2 Password is See Answer

Get Answers to Unlimited Questions

Join us to gain access to millions of questions and expert answers. Enjoy exclusive benefits tailored just for you!

Membership Benefits:

Unlimited Question Access with detailed Answers
Zin AI - 3 Million Words
10 Dall-E 3 Images
20 Plot Generations
Conversation with Dialogue Memory
No Ads, Ever!
Access to Our Best AI Platform: Flex AI - Your personal assistant for all your inquiries!

Become a Member