A) 6
B) 8
C) 5
D) 9
Correct Answer: D
Solution :
\[\frac{^{n}{{P}_{5}}}{^{n-1}{{P}_{4}}}=9\Rightarrow \frac{n\,!}{(n-5)\,!}\times \frac{(n-5)\,!}{(n-1)\,!}=9\Rightarrow n=9\].You need to login to perform this action.
You will be redirected in
3 sec