Question

The common ratio of the geometric sequence $a_n=3^{n-1}$ is

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is C 3

Given equation is $a_n=3^{n-1}$

Substitute $n=1,2,3,4$ in the given equation, we get
$a_1=3^0=1$
$a_2=3^1=3$
So, we get the first and second value of the G.P.
Common ratio $=$ $\frac{\text{second number}}{\text{first number}}$
$=$ $\frac{3}{1}=3$
So, the common ratio is $3$.