Given ∑n=0∞rn=4\sum_{n=0}^{\infty} r^n = 4∑n=0∞rn=4. What is the value of ∑n=0∞rn2n\sum_{n=0}^{\infty} \frac{r^n}{2^n}∑n=0∞2nrn?
8/58/58/5
4/34/34/3
222
3/23/23/2