Question

$ 1 + \left(\frac{1}{3} + \frac{1}{3^{2}}\right) + \left(\frac{1}{3^{3} } + \frac{1}{3^{4}} + \frac{1}{3^{5}}\right) + ....$ sum of the terms in the nth bracket =

• A. $\frac{(3^n - 1)^3}{2.4^{n - 1}}$
• B. $\frac{3^n - 1}{2.3^{(n - 1) (n+2) / 2 }}$
• C. $\frac{3^n + 1}{3.7^{n - 1}}$
• D. $\frac{3^{n- 1}}{2^{n + 1}}$

Answer 1

Answer: (B)

Correct answer is (b) $\frac{3^n - 1}{2.3^{(n - 1) (n+2) / 2 }}$