- 580

- 0

**1. Homework Statement**

If [tex]\sum^{n}_{r=0} \frac{1}{^{n}C_{r}} = a[/tex], then find the value of [tex]\sum^{n}_{r=0} \frac{r}{^{n}C_{r}}[/tex] in terms of a and n.[/tex]

**3. The Attempt at a Solution**

I tried to write down the terms of both the series, but to no avail. i cant think of anything.Please shed some light.