Question

The number of permutations of $n$ objects taken $r$ at a time is determined by the following formula:

• A. $\frac{r!}{(r-n)!}$
• B. $\frac{n!}{r!(n-r)!}$
• C. $\frac{r!}{(n-r)!}$
• D. $\frac{n!}{(n-r)!}$

Answer 1

The correct option is D $\frac{n!}{(n-r)!}$

The number of permutations of $n$ objects taken $r$ at a time is determined by
$P(n,r)=\frac{n!}{(n-r)!}$