SOLUTION: how many ways to arrange 7 books on a shelf when there are only 5 places on it?

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Question 555238: how many ways to arrange 7 books on a shelf when there are only 5 places on it?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
P(n,r) = (n!)/((n-r)!)

P(7,5) = (7!)/((7-5)!)

P(7,5) = (7!)/(2!)

P(7,5) = (7*6*5*4*3*2!)/(2!)

P(7,5) = 7*6*5*4*3

P(7,5) = 2520


So there are 2,520 ways.

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