Question

The first term of a geometric series is 3, and the sum of the first term and the second term is 15. What is the sum of the first six terms?

a) 1,023

b) 3,906

c) 4,095

d) 11,718

Answer 1

Sum of n terms in a geometric progression is given by Sn = a1 (1 - r^n) / (1 -r)

3( 1 - 4^6) / (1-4)

= 4,095