Let T_r be the r^th term of an A.P. If for some m, T_m =1/25, T_25=1/20, and 20 Σ_r =1^25 T_r =13, then 5 m Σ_r = m^2 m T_r is equal to

Let $\displaystyle \mathrm{T}_{\mathrm{r}}$ be the $\displaystyle \mathrm{r}^{\text {th }}$ term of an A.P. If for some $\displaystyle \mathrm{m}, \mathrm{T}_{\mathrm{m}}=\frac{1}{25}, \mathrm{~T}_{25}=\frac{1}{20}$, and $\displaystyle 20 \sum_{\mathrm{r}=1}^{25} \mathrm{~T}_{\mathrm{r}}=13$, then $\displaystyle 5 \mathrm{~m} \sum_{\mathrm{r}=\mathrm{m}}^{2 \mathrm{~m}} \mathrm{~T}_{\mathrm{r}}$ is equal to