==>\({f_1} = n\,\left( {\frac{v}{{v - {v_S}}}} \right)\)
\( = n\,\left( {\frac{{340}}{{340 - 34}}} \right) = \frac{{340}}{{306}}n\)
and \({f_2} = n\,\left( {\frac{{340}}{{340 - 17}}} \right) = n\,\left( {\frac{{340}}{{323}}} \right)\)
\( \Rightarrow \)\(\frac{{{f_1}}}{{{f_2}}} = \frac{{323}}{{306}} = \frac{{19}}{{18}}\)