9514 1404 393
Answer:
D. 21/2
Explanation:
It is probably easiest to add up the three terms.
For n=1, the first term is ...
8(1/4)^(0) = 8
The second term is ...
8(1/4)^1 = 2
The third term is ...
8(1/4)^2 = 8/16 = 1/2
The sum of the series is ...
8 + 2 + 1/2 = (16 +4 +1)/2 = 21/2