If a₁, a₂, a₃, ……., a_n is a G.P. having common ratio r and k is a natural number such that 3 < k < n, then r is equal to :

1. $\dfrac{a$k}{a{1}}

2. $\dfrac{a$1}{a2}

3. $\dfrac{a$k}{a{n-3}}

4. $\dfrac{a${k-1}}{a{k-2}}

The common ratio of the G.P. $-\dfrac{3}{4}, \dfrac{1}{2}, -\dfrac{1}{3}, \dfrac{2}{9}, \dots$ is :

1. $-\dfrac{4}{3}$

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

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

4. $-\dfrac{3}{8}$

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 nth term of the G.P. x³, x⁵, x⁷, …….. is :

1. x^{(2n - 1)}

2. x^{(2n + 3)}

3. x^{(2n + 1)}

4. x^{3n + 2}