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I have $3$ different mathematics textbooks, $2$ different psychology textbooks, and $2$ different chemistry textbooks. In how many ways can I place the $7$ textbooks on a bookshelf, in a row?

 Apr 19, 2024
 #1
avatar+1083 
0

 

 

                 7!             5040  

7P7  =  –––––––  =  ––––––  =  5040       

             (7 – 7)!           1   

 

You might question zero in the denominator,   

but zero factorial is defined as 1 so it's okay.  

.

 Apr 20, 2024
edited by Bosco  Apr 20, 2024

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