Mohan purchased a house for Rs 30000 and its value is depreciating at the rate of 25% per year.

Value of the house after three years $=\mathrm{P}\left(1-\frac{\mathrm{R}}{100}\right)^{\mathrm{n}}$

$\Rightarrow 30,000\left(1-\frac{25}{100}\right)^{3}$

$=30,000(0.75)^{3}$

$=12,656.25$

Thus, the value of the house after three years will be Rs $12,656.25$.