Question 1105467
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I think you meant to write "books" instead of "boxes". 


We have five books but only enough space for three of them. 


Label the three empty spaces as
Slot A
Slot B
Slot C


There are 5 choices for slot A.
After you've picked a book to go into slot A, there are 5-1 = 4 choices for slot B since you cannot have a book occupy more than one slot at a time.
For slot C, there are 3 choices left.


So have 5*4*3 = 20*3 = 60 different permutations.


If you wish to use a formula, then you can use the nPr formula
nPr = (n!)/(n-r)!
where you plug in n = 5 and r = 3 to get the same result of 60


Answer: 60
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