Question

find n if, 10Pn-1:11Pn-2=30:11​

Answer 1

The value of n is  "7 0r 18".

Step-by-step explanation:

We have,

P(10, n - 1) : P(11, n - 2) = 30: 11

⇒ $\dfrac{10!}{(10 - n +1)!} : \dfrac{11!}{(11 - n +2)!}=30:11$

⇒$\dfrac{10!}{(11- n )!} : \dfrac{11!}{(13 - n)!}=30:11$

⇒$\dfrac{(12-n)(13-n)(11-n)!}{(11-n)!(11)} =\dfrac{30}{11}$

⇒$(12-n)(13-n)=30$

By inspection method,

n = 7 0r 18

Hence, the value of n is  7 0r 18.

Answer 2

Step-by-step explanation:

i hope it's helpful for you