Question

Use the formula for nPr to evaluate the following expression. 5P5

Answer 1

Answer: 120

Step-by-step explanation:

The permutation of n things taken r at a time is given by expression :-

$^nP_r$

The formula to evaluate $^nP_r$ is given by :-

$^nP_r=\dfrac{n!}{(n-r)}$

Then , $^5P_5$  will be :-

$^5P_5=\dfrac{5!}{(5-5)!}$

Since , $n!=n(n-1)(n-2).......(2)(1)$

Then , $^5P_5=\dfrac{5\times4\times3\times2\times1}{0!}=120\ \ \ \text{Also,}0!=1$

Therefore, the value of the expression $^5P_5=120$