Question

What is the sum of the first five terms of a geometric series with a1=20 and r=1/4

Answer 1

Answer: 26.640625

Explanation:

Answer 2

The sum of a geometric sequence is:

s(n)=a(1-r^n)/(1-r), a=initial term and r=common ration so

s(n)=20(1-0.25^n)/(1-0.25)

s(5)=20(1-0.25^5)/(0.75)

s(5)=26.640625