\(C=\frac{1}{1.2}+\frac{1}{2.7}+\frac{1}{5.7}+\frac{1}{5.13}+\frac{1}{8.13}+\frac{1}{8.19}\)
\(\frac{3}{2}C=\frac{3}{2}\)(\(\frac{1}{1.2}+\frac{1}{2.7}+\frac{1}{5.7}+\frac{1}{5.13}+\frac{1}{8.13}+\frac{1}{8.19}\))
\(\frac{3}{2}C=\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+\frac{3}{10.13}+\frac{3}{13.16}+\frac{3}{16.19}\)
\(\frac{3}{2}C=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+\frac{1}{10}-\frac{1}{13}+\frac{1}{13}-\frac{1}{16}+\frac{1}{16}-\frac{1}{19}\)
\(\frac{3}{2}C=1-\frac{1}{19}=\frac{18}{19}\)
\(C=\frac{18}{19}:\frac{3}{2}=\frac{12}{19}\)