Answer
The number of ways to select 8 books out of 40 books is $76,904,685$.
Work Step by Step
We know that:
${}_{n}{{C}_{r}}=\frac{n!}{r!\left( n-r \right)!}$
So, from the information,
$\begin{align}
& n=40 \\
& r=8
\end{align}$
Then, we know that to find the number of combinations of 40 things taken 8 at a time, we applying the above formula:
$\begin{align}
& {}_{40}{{C}_{8}}=\frac{40!}{8!\left( 40-8 \right)!} \\
& =\frac{40!}{8!32!} \\
& =\frac{40\times 39\times 38\times 37\times 36\times 35\times 34\times 33\times 32!}{8!\times 32!} \\
& =76,904,685
\end{align}$
Thus, the number of ways to select 8 books out of 40 books are $76,904,685$.
