We know that, when compound interest is computed half-yearly, time will be $2t$ and rate will be $\dfrac{r}{2}.$
Amount $ = \text{P} \left[ 1 + \left( \dfrac{\dfrac{r}{2}}{100} \right) \right]^{2t}$
$\Rightarrow \boxed{\text{Amount} = \text{P} \left[ 1 + \dfrac{r}{200} \right]^{2t}}$
Now, $18522 = \text{P} \times \left[ 1 + \dfrac{10}{200} \right]^{2 \times 1.5}$
$\Rightarrow 18522 = \text{P} \times \left[ \dfrac{21}{20} \right]^{3}$
$\Rightarrow 18522 = \text{P} \left( \dfrac{9261}{8000} \right)$
$\Rightarrow \text{P} =$ ₹ $\; 16000$
$\therefore$ The amount, in rupees, that the person had interested is ₹ $\; 16000.$
Correct Answer $: 16000$