Last answered:

21 Jan 2021

Posted on:

30 Dec 2020


Resolved: Variations with Repetition (Quiz 3)

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, Jimmy
1 answers ( 0 marked as helpful)
Posted on:

21 Jan 2021

Hi,   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!

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