The compound interest on Rs 1800 at 10% per annum for a certain period of time is Rs 378.

$\mathrm{CI}=\mathrm{P}\left(1+\frac{\mathrm{R}}{100}\right)^{\mathrm{n}}-\mathrm{P}$

$\Rightarrow 378=1,800\left(1+\frac{10}{100}\right)^{\mathrm{n}}-1,800$

$1,800\left(1+\frac{10}{100}\right)^{\mathrm{n}}=2,178$

$\left(1+\frac{10}{100}\right)^{\mathrm{n}}=\frac{2,178}{1,800}$

$(1.1)^{\mathrm{n}}=1.21$

$(1.1)^{\mathrm{n}}=(1.1)^{2}$

On comparing both the sides, we get:

n = 2

Thus, the required time is two years.