Question

Which term of the GP $2,8,32$, ... is $131072$?

• A. $6^{th}$
• B. $7^{th}$
• C. $8^{th}$
• D. $9^{th}$

Answer 1

The correct option is D $9^{th}$

In given GP, we have $a=2,r=4,a_n=a{r}^{n-1}$

We know that nth term of a GP is given by $a{r}^{n-1}$

$\therefore 2\times 4^{n-1}=131072$
$\Rightarrow 4^{n-1}=65536=4^8$
$\Rightarrow n=9$