GP
a=1/3 r= 1/3 n=6
\\\boxed{S_n=\frac{a(1-r^n)}{1-r}}\\\\ S_6=\frac{\frac{1}{3}(1-(\frac{1}{3})^6)}{1-\frac{1}{3}}}\\\\ S_6=\frac{\frac{1}{3}(1-\frac{1}{3^6})}{\frac{2}{3}}}\\\\ S_6=\frac{1}{\not{3}}(1-\frac{1}{3^6})\times \frac{\not{3}}{2}\\\\ S_6=\frac{1}{2}(1-\frac{1}{3^6})\\\\
0.5×(1−(136))=364729=0.4993141289437586
GP
a=1/3 r= 1/3 n=6
\\\boxed{S_n=\frac{a(1-r^n)}{1-r}}\\\\ S_6=\frac{\frac{1}{3}(1-(\frac{1}{3})^6)}{1-\frac{1}{3}}}\\\\ S_6=\frac{\frac{1}{3}(1-\frac{1}{3^6})}{\frac{2}{3}}}\\\\ S_6=\frac{1}{\not{3}}(1-\frac{1}{3^6})\times \frac{\not{3}}{2}\\\\ S_6=\frac{1}{2}(1-\frac{1}{3^6})\\\\
0.5×(1−(136))=364729=0.4993141289437586