How many terms are there in the G.P. 3, 6, 12, ..., 384?
Answer: B
Here, \(a=3, r=2, a_n=384\). We use the formula \(a_n = ar^{n-1}\). \(384 = 3 \times 2^{n-1} \Rightarrow 128 = 2^{n-1}\). Since \(128 = 2^7\), we have \(2^7 = 2^{n-1}\). Equating the powers gives \(7=n-1\), so \(n=8\). There are 8 terms.