Question

Answer 1

\(=\dfrac{6}{4}\times\left(\dfrac{4}{6\times10}+\dfrac{4}{10\times14}+...+\dfrac{4}{62\times66}+\dfrac{4}{66\times70}\right)\\ =\dfrac{3}{2}\times\left(\dfrac{1}{6}-\dfrac{1}{10}+\dfrac{1}{10}-\dfrac{1}{14}+...+\dfrac{1}{62}-\dfrac{1}{66}+\dfrac{1}{66}-\dfrac{1}{70}\right)\\ =\dfrac{3}{2}\left(\dfrac{1}{6}-\dfrac{1}{70}\right)=\dfrac{3}{2}\times\dfrac{16}{105}=\dfrac{8}{35}\)

Answer 2

8/35