120 + 130 + 142 + 156 + 172 + 190 + 1110 + 1132 is equal to :

Answer: Option C

$$\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}+\frac{1}{90}$$      $$+\frac{1}{110}$$   $$+\frac{1}{132}$$
$$=\left(\frac{1}{4\times 5}\right)+\left(\frac{1}{5\times 6}\right)+\left(\frac{1}{6\times 7}\right)$$       $$+.....+$$   $$\left(\frac{1}{11\times 12}\right)$$
$$=\left(\frac{1}{4}-\frac{1}{5}\right)+\left(\frac{1}{5}-\frac{1}{6}\right)+\left(\frac{1}{6}-\frac{1}{7}\right)$$       $$+.....+$$   $$\left(\frac{1}{11}-\frac{1}{12}\right)$$
$$=\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+.....$$      $$+\frac{1}{11}$$  $$-\frac{1}{12}$$
$$\begin{array}{rl}& =\frac{1}{4}-\frac{1}{12}\\ & =\frac{3-1}{12}\\ & =\frac{2}{12}\\ & =\frac{1}{6}\end{array}$$