SOLUTION
Arranging r books from n books is given as n permutation r
[tex]\begin{gathered} ^nP_r\text{ is the number of ways of arranging r books from n books } \\ \\ n=10 \\ r=4 \\ \\ ^{10}P_4=5040\text{ \lbrack input into calculator \rbrack} \end{gathered}[/tex]
