The common ratio of the G.P. $\dfrac{1}{a^3x^3},\ ax,\ a^5x^5,\ \dots$ is :

1. $\dfrac{1}{a^2x^2}$

2. $\dfrac{1}{a^4x^4}$

3. a²x²

4. a⁴x⁴

The common ratio of the G.P. 0.15, 0.015, 0.0015, …… is :

1. 0.1

2. 0.01

3. 1

4. 0.001

The 10th term of the G.P. 1, −a, a², −a³, …….. is :

1. a⁹

2. −a¹⁰

3. −a¹¹

4. −a⁹

The first term and the common ratio of the G.P. 3, $\dfrac{3}{2}, \dfrac{3}{4}$, ………. are respectively :

1. 3 and 2

2. 3 and $\dfrac{1}{2}$

3. 3 and $\dfrac{3}{2}$

4. $\dfrac{3}{2}$ and $\dfrac{1}{2}$