Question

Let $S_k,k=1,2,3,\dots \dots$ denote the sum of infinite geometric series whose first term is $\left(k^2-1\right)$ and the common ratio is $\frac{1}{k}$. Find the addition of the digits of sum $\sum _{k=1}^{\infty }\frac{S_k}{2^{k-1}}$.

Answer 1

Answer: 5

Correct answer is (e)