If ` a_(n) = sum_(r=0)^(n) (1)/(""^(n)C_(r)) ` , find the
value of ` sum_(r=0)^(n) (r)/(""^(n)C_(r))`

Explanation

To solve the problem, we need to find the value of

\[ P = \sum_{r=0}^{n} \frac{r}{\binom{n}{r}}. \]

### Step 1: Rewrite the summation
We start with the expression for \( P \):
...