The number of different arrangements of books is 210
Permutation in mathematics can be calculated by using the formula
nPr = [tex]\frac{n!}{(n - r)!} [/tex]
where
nPr = [tex]\frac{7!}{(7-3)!} [/tex]
nPr = [tex]\frac{5040}{24} [/tex]
nPr = 210
Therefore, the required number of ways is 210
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