<PRE><B>Question 346754</B>
there are 4 types of books (math, chem, hist, language) so there are 4! ways to arrange the type of book.
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Within each topic there are 4! ways to arrange the 4 math books
3! ways to arrange the chem books
2! ways to arrange the hist books
1! ways to arrange the languate book

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in total=ways to arrange type * ways to arrange books within each type
there are  4!*(4!*3!2!*1)=24*24*6*2=6912 ways to arrange the books
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