Answer:
0.8
Step-by-step explanation:
Given the formula for the geometric series expressed as;
[tex]\sum \left \{ {3} \atop {1}} \right 1.3(0.8)^{n-1}[/tex]
The nth term of a geometric progression is expressed as;
[tex]T_n = ar^{n-1}\\[/tex]
a is the first term
r is the common ratio
Comparing both equations;
[tex]0.8^{n-1} = r^{n-1}\\Cancel \ the \ powers\\0.8 = r\\r = 0.8\\[/tex]
Hence the value of r of the geometric series is 0.8
