Compute the geometric series.
3 + 15 + 75 + 375 + 1875 + 9375 + 46,875

3+15+75+375+1875+9375+46875+234375 = 292,968 

If a sequence is geometric there are ways to find the sum of the first n terms, 
denoted Sn, without actually adding all of the terms. 

To find the sum of the first n terms of a geometric sequence use the formula 
Sn = a1(1 - r^n)/1 - r, r ≠ 1 
where n is the number of terms, a1 is the first term and r is the common ratio. 
The sum of the first n terms of a geometric sequence is called geometric series. 

 
292,968 do u get it