The sum of first 20 terms of the sequence $0.7, 0.77, 0.777, \ldots$ is (1) $\frac{7}{81}(179-10^{-20})$ (2) $\frac{7}{9}(99-10^{-20})$ (3) $\frac{7}{81}(179+10^{-20})$ (4) $\frac{7}{9}(99+10^{-20})$
The sum of first 20 terms of the sequence $0.7, 0.77, 0.777, \ldots$ is\\
(1) $\frac{7}{81}(179-10^{-20})$\\
(2) $\frac{7}{9}(99-10^{-20})$\\
(3) $\frac{7}{81}(179+10^{-20})$\\
(4) $\frac{7}{9}(99+10^{-20})$