Question

Which term of the G.P. 2, 8, 32, 128, ......... is 131072?

Options

• 9th

• 10th

• 8th

• 12th

Answer 1

9th

Explanation:

Here, $$a = 2$$ and $$r = 4$$. Solving $$2\times4^{n - 1} = 131072 = 2^{17}$$ gives $$2n - 1 = 17$$, so $$n = 9$$.