SOLUTION: What is the answer in the following? •P(n,n-1)=6 •P(16,4)=208•P(n,2)

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Question 1178176: What is the answer in the following?
•P(n,n-1)=6
•P(16,4)=208•P(n,2)
Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


•P(n,n-1)=6

P(n,n-1) has the same value as P(n,n), which is n!:

P(n,n-1) = n(n-1)...(3)(2) = n(n-1)...(3)(2)(1) = n!

So the first problem is

n! = 6

Trivially, the answer is n=3.

•P(16,4)=208•P(n,2)

16%2A15%2A14%2A13+=+208%2A%28n%28n-1%29%29
16%2A15%2A14%2A13+=+16%2A13%28n%28n-1%29%29
15%2A14+=+n%28n-1%29

Clearly n=15.