Question

find n and r in a geometric series for which sn=93, an=48 and a1=3.

Answer 1

3r^(n-1) = 48

r^(n-1) = 16
2^4 = 16, so
r=2 and n=5
check:
S5 = 3(2^5-1) = 3*31 = 93