How many terms are there in the G.P. 3, 6, 12, 24, … , 384 ?

Question:
How many terms are there in the G.P. 3, 6, 12, 24, … , 384 ?

[A].

8

[B].

9

[C].

10

[D].

11

Answer: Option A

Explanation:

Here a = 3 and r =	6	= 2. Let the number of terms be n.
	3

Then, tn = 384     arn-1 = 384

3 x 2n – 1 = 384

2n-1 = 128 = 27

n – 1 = 7

n = 8

Number of terms = 8.