Answer
The number of selections $40_{{C}{_{8}}}$ = 76,904,685
Work Step by Step
Total number of books in the list = 40
Number of books have to choose = 8
To find the number of ways of selection we determine by the formula $n_{{C}{_{r}}}$ = $\frac{n!}{(n - r)! r!}$
The number of selections $40_{{C}{_{8}}}$ = $\frac{40!}{(40 - 8)! 8!}$
= $\frac{40!}{32! . 8!}$
= $\frac{40\times39\times38\times37\times36\times35\times34\times33\times32!}{32! .(8\times7\times6\times5\times4\times3\times2\times1)}$
= $\frac{40\times39\times38\times37\times36\times35\times34\times33}{8\times7\times6\times5\times4\times3\times2\times1}$
= 76904685
