‘Tn’ represents the nth term of a G.P. series.
Tn = arn-1
Sum of a G.P. series is represented by the formula, Sn = a\(\frac{1- r^n}{1-r}\), when |r|<1.
‘Sn’ represents the sum of the G.P. series up to nth terms,
‘a’ represents the first term,
‘r’ represents the common ratio and
‘n’ represents the number of terms.
Here,
a = 27
r = (ratio between the n term and n-1 term)\(\frac{1}{3}\)
n = 10 terms