(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

P(n, 4) = 40[P(n-1, 2)]

2. Relevant equations

???

3. The attempt at a solution

I boiled this down to the equation n!/(n-4)! = 40[(n-1)!/(n-3)!]. The problem is, I have no idea how to perform the correct operations on these factorials. I found the answer to be n = 8, but this was just trial and error. The factorials don't seem to behave like regular numbers, where cross multiplication or LCD would work. The text book this comes from is old, and only glances over the factorials. I suppose a teacher's edition would provide more info. Any hints or tips, as usual, are appreciated.

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# Homework Help: Factorial Algebra

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