Question Detail
Question
Find the sum of first 8 terms of GP 2, 4, 8, ...
Correct Answer
Option A is the correct answer.
Detailed Explanation
S_8 = a(r^8−1)/(r−1)=2(2^8−1)/(2−1)=2(256−1)=2×255=510.
Hint
Use S_n formula.