Answer:
2.68928
Step-by-step explanation:
The sum of geometric series formulas is
[tex]S_{n}=\frac{a_{1}(1-r^{n} )}{1-r}[/tex]
Where [tex]S_{n}[/tex] is the Sum, [tex]a_{1}[/tex] is the first member of the series, r the common ratio (in this case 0.8) and n is the number of terms.
Using the formula:
[tex]S_{n}=\frac{0.8(1-0.8^{5} )}{1-0.8}[/tex]
Then
S_{n}=2.68928
