A geometric sequence has first term 3 and common ratio 2. What is the sum of the first 5 terms?
Correct: A
The sum of the first n terms of a geometric sequence with first term a and common ratio r is a(1-r^n)/(1-r). In this case, a=3, r=2, and n=5. So the sum is 3(1-2^5)/(1-2) = 3(-31)/(-1) = 93.