Answer
$=\dfrac {3}{11}$
Work Step by Step
$0.\overline {27}=0.272727...=\dfrac {27}{100}+\dfrac {27}{100^{2}}+\dfrac {27}{100^{3}}+\ldots =\dfrac {a_{1}}{1-r}=\dfrac {\dfrac {27}{100}}{1-\dfrac {1}{100}}=\dfrac {\dfrac {27}{100}}{\dfrac {99}{100}}=\dfrac {27}{99}=\dfrac {3}{11}$