l, $\frac{5}{2.4}$ + $\frac{5}{4.6}$ + $\frac{5}{6.8}$ +......+ $\frac{5}{2016.2018}$
⇔ $\frac{B}{5}$ = $\frac{1}{2.4}$ + $\frac{1}{4.6}$+ $\frac{1}{6.8}$+......+ $\frac{1}{2016.2018}$
⇔ B.$\frac{2}{5}$= $\frac{2}{2.4}$+ $\frac{2}{4.6}$+ $\frac{2}{6.8}$+......+ $\frac{2}{2016.2018}$
⇔ B.$\frac{2}{5}$= $\frac{1}{2}$ - $\frac{1}{4}$+ $\frac{1}{4}$ -$\frac{1}{6}$ + $\frac{1}{6}$ -$\frac{1}{8}$ +.....+ $\frac{1}{2016}$ - $\frac{1}{2018}$
⇔ B= $\frac{5050}{2018}$