Answer:
Step-by-step explanation:
According to sigma notation we have a GP with:
- The first term of 8
- The common ratio of 1/4
Find the sum of the first 3 terms:
- Sₙ = a₁(1 - rⁿ) / (1 - r)
- S₃ = 8*(1 - 1/4³) / (1 - 1/4) = 8*(1 - 1/64) / (3/4) = 8*63/64 * 4/3 = 21 / 2
Correct choice is B
