\(A=\frac{1}{3.8}+\frac{1}{6.12}+\frac{1}{9.16}+...+\frac{1}{1512.2020}\)
\(A=\frac{1}{5}.\left(\frac{1}{3}-\frac{1}{8}+\frac{1}{6}-\frac{1}{12}+\frac{1}{9}-\frac{1}{12}+...+\frac{1}{1512}-\frac{1}{2020}\right)\)
\(A=\frac{1}{5}.\left(\frac{1}{3}-\frac{1}{2020}\right)\)
\(A=\frac{1}{5}.\frac{2017}{6060}\)
\(A=\frac{2017}{30300}\)