\[1;\frac{1}{10};\frac{1}{100};\ldots\]
\[b_{1} = 1;\ \ b_{2} = \frac{1}{10};\ \ \]
\[q = \frac{1}{10}\ :1 = \frac{1}{10};\]
\[S = \frac{b_{1}}{1 - q} = \frac{1}{1 - \frac{1}{10}} = 1\ :\frac{9}{10} = \frac{10}{9} = 1\frac{1}{9}.\]
\[Ответ:1\frac{1}{9}.\]