The sum of 7 terms of the G.P. 3, 6, 12, ………. is :

1. 181

2. 241

3. 381

4. 421

The sum of the first two terms of a G.P. is −4 and the fifth term is 4 times the third term. Then, the first term of the G.P. is :

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

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

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

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

The product of first five terms of a G.P. with first term a and common ratio r > 1 is equal to :

1. $\dfrac{a(r^5 - 1)}{r - 1}$

2. ar⁴

3. a⁵r¹⁰

4. $\dfrac{a(r^5 - 1)}{r}$

If 5th, 8th and 11th terms of a G.P. are x, y and z respectively, then which one of the following is correct?

1. y² = x²z²

2. y² = x² + z²

3. y² = xz

4. xyz = 1