Sn=x(1-q^n)/(1-q) Xn=x(q^(n-1))
3=x(q^(n-1))=((0.5)^(n-1))x x=3/(1/2)^(n-1) x=3(2^(n-1))
93=3(2^(n-1))(1-1/2^n)/(1-1/2) (2^n -1 )3=93 2^n -1=31
2^n=32
2^n=2^5
n=5 x=3(2^(n-1))=48
