Summation of seriesHard

Sum of Arithmetic Progression Terms

Let T_r be the r^th term of an A.P. If for some m, T_m = $\frac{1}{{25}}$ , T₂₅ = $\frac{1}{{20}}$ and 20 $\sum\limits_{r = 1}^{25} {{T_r}}$ = 13, then $5m\sum\limits_{r = m}^{2m} {{T_r}}$ is equal to :

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