Question

Find the sum of the GP : 

0.15 + 0.015 + 0.0015 + …. To 6 terms

Answer 1

Sum of a G.P. series is represented by the formula, S_n = \(a \frac{1-r^n}{1-r}\) , when |r|<1. 

‘S_n’ represents the sum of the G.P. series up to n^th terms, ‘a’ represents the first term, ‘r’ represents the common ratio and ‘n’ represents the number of terms. 

Here,

a = 0.15 

r = (ratio between the n term and n-1 term) 0.015 ÷ 0.15 = 0.1 

n = 6 terms