Meena earns $\text{Rs. }9,000$ in a month by working $25\text{days}$. At the same rate, how many days must she work to earn $\text{Rs. }10,800$?

We can solve this question using the unitary method.
Given that earnings for $25\text{days}=\text{Rs. }9,000$

First, calculate Meena's earnings for a single day:

$$\text{Earnings per day}=\frac{9000}{25}=\text{Rs. }360\text{/day}$$

Now, let $x$ be the total number of days required to reach the target of $\text{Rs. }10,800$:

$$\text{Number of days }(x)=\frac{\text{Total Target Earnings}}{\text{Earnings per day}}$$

$$x=\frac{10800}{360}=\frac{1080}{36}=30\text{days}$$

Therefore, she must work for exactly $30\text{days}$ to reach that target amount.