If the first term, common ratio and the last term of a G.P. are a, r and l respectively, then the nth term from the end of the G.P. is given by :

1. lr^{n - 1}

2. lr^{1 - n}

3. $\dfrac{l}{r^{1 - n}}$

4. $\dfrac{l}{r^{n + 1}}$

The sum of n terms of a G.P. with first term a and common ratio r, when r = 1, is given by:

1. $S_n = \dfrac{a(1-r^n)}{1-r}$

2. $S_n = \dfrac{a(r^n-1)}{r-1}$

3. n²a

4. na

The 12th term of the G.P. 2, 4, 8, 16, ……. is :

1. 1024

2. 2048

3. 4096

4. 8192

Which term of the G.P. $\sqrt{3}, 3\sqrt{3}, 9\sqrt{3}, \dots$ is $729\sqrt{3}$ ?

1. 7th

2. 6th

3. 9th

4. 8th