the sum of the term in a geometric sequence
Sn=\(\frac{a1(1-r^n)}{1-r}\)
where
there are n terms
r is common ratio
a1 is first term
Sn=\(\frac{20(1-(1/4)^5)}{1-(1/4)}\)
Sn=\(\frac{20(1-(1/1024))}{3/4}\)
Sn=\(\frac{20(1023/1024)}{3/4}\)
Sn=\(\frac{1705}{64}\)
