Find the value of `r,` if
(i) `.^(11)P_(r)=990`
(ii) `.^(8)P_(5)+5*.^(8)P_(4)=.^(9)P_(r)`

Explanation

To solve the given problem, we need to find the value of \( r \) for two separate equations involving permutations. Let's break it down step by step.

### Part (i): Solve \( 11P_r = 990 \)

1. **Understand the formula**: The formula for permutations is given by:
\[ nP_r = \frac{n!}{(n-r)!} \]
...