Question

What is the some need help????​

Answer 1

The sum formula for a geometric sequaence is:

sum(n) = a1(1-r^n)/1-r

Where n is the number of terms, a1 is the first term and r is the common ratio:

s(8) = 3(1-1/2^8) / (1-1/2)

s(8) = 3(1-1/256) / 1/2

s(8) = 2 253/256 / 1/2

s(8) = 765/128

The answer is C.