Question

What is the sum of the first five terms of a geometric series with a = 10 andr
= 1/5?

Answer 1

12.496

Explanation:

Here, to calculate the sum of the first five terms of the series, we use the formula for the sum of terms in a geometric series.

Mathematically, that would be;

Sn = a(1-r^n)/1-r

where Sn = ?

a = 10

r = 1/5 = 0.2

n = 5

Substituting these values into the equation above, we have;

Sn = 10(1-(0.2)^5)/1-0.2

Sn = 10(0.99968)/0.8

Sn = 12.496