🛠️ Scheduled Maintenance | We’ll be undergoing scheduled maintenance and upgrades between 00:00 PST Jan 26th until 00:00 PST Jan 28th. There may be brief interruption of services in that period. We apologize for the inconvenience.

The 365 Data Science team is proud to invite you to our own community forum. A very well built system to support your queries, questions and give the chance to show your knowledge and help others in their path of becoming Data Science specialists.
Anybody can ask a question
Anybody can answer
The best answers are voted up and moderated by our team

Variations with Repetition (Quiz 3)

Variations with Repetition (Quiz 3)

Super Learner

Hi 365 team and aspiring data scientists,
I have a quick Q about the quiz no 3 in the “Computing Variations with Repetition” module. 

Why is 8 to the power of 4 (8^4) not the correct answer? Can someone help me explain this? 
I would very much appreciate it.
Thank you,

Hey 365 team, can someone help with this query? I have been waiting for weeks now 🙁

4 days
1 Answer

Super Learner

Try thinking about the quiz the following way:

  • How many different 4-letter codes are there so that each letter is one of the letters in the word “password”?

The “trick” here is that the word “password” has only 7 distinct letters: P, A, S, W, O, R, D. Therefore we need to arrange 4 out of 7 letters, allowing for repetition and their order is relevant (each 4-letter code is a unique code; the lock would not open if the code was PASW and you typed WASP). So you end up with:
V(n=7,p=4) = 7^4
Hope this helps!

Thanks a lot for this, Jacob! This finally clears my doubt 🙂 truly appreciate your effort.

3 days