Answer:
The sum of the geometric series = 11.93
Step-by-step explanation:
The sum of the first n terms of a geometric series is:

From the given expression:
The first term, a = 3
The common ratio, r = 3/4 = 0.75
The number of terms, n = 18
Substitute the given values into the formula above

The sum of the geometric series = 11.93