A fair $n ( n > 1 )$ faces die is rolled repeatedly until a number less than $n$ appears. If the mean of the number of tosses required is $\frac { n } { 9 }$, then $n$ is equal to
A fair $n ( n > 1 )$ faces die is rolled repeatedly until a number less than $n$ appears. If the mean of the number of tosses required is $\frac { n } { 9 }$, then $n$ is equal to