The first term of this series is a = 19.2, and the common ratio is r = 1/2. Note that 1/2 of 19.2 is 9.6, and that 1/2 of 9.6 is 4.8, and so on.
The sum of such a geometric series is
a
S = --------
1-r
which in this case comes out to:
19.2
S = -------------- = 38.4 (This is the infinite sum of the given geometric series.)
1 - (1/2)
