Mathematics - Sequence & Series Question with Solution | TestHub

For an A.P., the middle term of the first $2m-1$ terms equals their average: $t_m=\frac{S_{2m-1}}{2m-1}$. Applying this to both progressions, their $m$th-term ratio equals their sum ratio at $n=2m-1$. For $m=17$, use $n=33$: $168:103$, option B.