Question

The 4th term of a G.P is square of its second term and the first term is - 3. Determine the Common Ratio of the G.P.

• A. r = -3
• B. r = -12
• C. r = -9
• D. r = -5

Answer 1

The correct option is A

r = -3

Given: $a=-3$ and $a_4=(a_2{)}^2$
$\Rightarrow a{r}^3=(ar{)}^2$ $[\because a_n=a{r}^{n-1}]$
$\Rightarrow a{r}^3=a^2{r}^2\Rightarrow r=a\Rightarrow r=-3$