What is the value of 10.2 + 10.02 + 10.002 + \,..... upto 9 terms?

Answer: Option C

$$\begin{array}{rl}& \frac{1}{0.2}+\frac{1}{0.02}+\frac{1}{0.002}+.....9^{\text{th}}\text{ term}\\ & \text{ = }\frac{1}{2}\left[10+100+1000+.....9^{\text{th}}\text{ term}\right]\\ & =\frac{1}{2}\left[1111111110\right]\\ & =555555555\end{array}$$