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I have $4$ different mathematics textbooks and $3$ different psychology textbooks. In how many ways can I place the $7$ textbooks on a bookshelf, in a row, if there must be a mathematics textbook exactly in the middle, and all the psychology textbooks are together?

 Jan 23, 2025
 #1
avatar+130317 
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If all the Psychology textbooks are together then so are all the Math textbooks

Arrange the math textbooks in 4! ways  and the Psychology textbooks in 3! ways

And either the Math textbooks or the Psychology  can come first

 

2 * 4! * 3!  =    288 ways

 

cool cool cool

 Jan 23, 2025

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