Question

If the ${10}^{th}$ term of a GP is 9 and $4^{th}$ term is 4, then its $7^{th}$ term is

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

Let a be the first term and r be the common ratio of GP then,
$T_{10}=9\Rightarrow a{r}^9=9T_4=4\Rightarrow a{r}^3=4T_7=a{r}^6=(a{r}^9.a{r}^3{)}^{\frac{1}{2}}=(9\times 4{)}^{\frac{1}{2}}=6$