Find the sum of indicated number of terms .7,.07,.007,......;100 terms
7 (0.1 + 0.01 + 0.001 + .......100 terms ) here a=0.1 & r=0.1 & n=100
7 ( 0.1 ( 1 - (0.1)n ) / 1- 0.1 )
7 ( 1/10 ( 1 - ( 1/10 )100 ) / 9/10 )
= 7 ( ( 1 - ( 1/10 )100 ) / 9 )
= 7 /9 ( 1 - ( 1/10 )100 )