Geometric Series

the 2nd sequence = $\frac {n}{3}$ and 1st sequence is = $\frac {n}{9}$

that means =1st term x 3 = 2nd term

and , 2nd term x 3 = 3rd term

so, the ratio is 3

$\displaystyle r = \frac {a_{n + 1}}{a_n}$

$\displaystyle r = \frac {3n}{n} = 3$