B = $\frac{36}{1.3.5}$ + $\frac{36}{3.5.7}$ + $\frac{36}{5.7.9}$ +...+ $\frac{36}{25.27.29}$
B = 9 . ($\frac{4}{1.3.5}$ + $\frac{4}{3.5.7}$ + $\frac{4}{5.7.9}$ +...+ $\frac{4}{25.27.29}$)
B = 9 . ($\frac{1}{1.3}$ - $\frac{1}{3.5}$ + $\frac{1}{3.5}$ - $\frac{1}{5.7}$ +...+ $\frac{1}{25.27}$ - $\frac{1}{27.29}$)
B = 9 . ($\frac{1}{3}$ - $\frac{1}{27.29}$)
B = 3 - $\frac{1}{87}$
B = $\frac{261}{87}$ - $\frac{1}{87}$
B = $\frac{260}{87}$