Try this suggested option:
1. rule for the sum of this geometric series is:
[tex]S= \frac{a_1}{1-r};[/tex]
2. according to the rule above:
[tex]S= \frac{343}{1+ \frac{1}{7}}= \frac{343*7}{8}=300.125[/tex]
answer: 300.125
P.S. note, that in this formula a₄ is not included.
