select the correct answer.\nwhat is the number of possible permutations of 8 objects taken 4 at a time?\na…

select the correct answer.\nwhat is the number of possible permutations of 8 objects taken 4 at a time?\na. 24\nb. 70\nc. 1,680\nd. 40,320
Answer
Explanation:
Step1: Recall permutation formula
The formula for permutations is $P(n,r)=\frac{n!}{(n - r)!}$, where $n$ is the total number of objects and $r$ is the number of objects taken at a time. Here $n = 8$ and $r=4$.
Step2: Calculate factorial values
$n!=8! = 8\times7\times6\times5\times4\times3\times2\times1$, $(n - r)!=(8 - 4)!=4!=4\times3\times2\times1$. Then $P(8,4)=\frac{8!}{(8 - 4)!}=\frac{8\times7\times6\times5\times4!}{4!}$.
Step3: Simplify the expression
The $4!$ in the numerator and denominator cancels out. So $P(8,4)=8\times7\times6\times5=1680$.
Answer:
C. 1,680