Answer:
65535
Step-by-step explanation:
The sum to n terms of a geometric sequence is
[tex]S_{n}[/tex] = [tex]\frac{a(r^n-1)}{r-1}[/tex]
where a is the first term and r the common ratio, thus
[tex]S_{8}[/tex] = [tex]\frac{3(4^8-1|)}{4-1}[/tex]
= [tex]\frac{3(4^8-1)}{3}[/tex]
= [tex]4^{8}[/tex] - 1 = 65536 - 1 = 65535
