Expected Income Question
Think of all the possible outcomes. For example, if your first ball is red you loose 1 rupee (this has probability 1/2), if you instead get one green ball and then one red ball you end up with  0 rupees (this has probability 1/4), if instead you get at first 2 green balls and then a red one, you end up with 1 rupee (this has probability 1/8), etc. 

The expected value is 

$$E(V)=(-1)\frac12+(0)\frac14+(1)\frac18+(2)\frac1{16}\dots=\sum_{n=1}^\infty(n-2)\frac{1}{2^n}=0$$

The last equality comes from two well-known results: $\sum_{n=1}^\infty\frac{n}{2^n}=2$ and $\sum_{n=1}^\infty\frac{1}{2^n}=1$