Sushant spent $18\%$ of his monthly salary on buying electronic goods and $32\%$ of the monthly salary on repair work in his house. Out of remaining amount he invested $42\%$ in fixed deposit. If he was left with $\text{Rs. }12,325$, how much is his annual salary?

Let Sushant's monthly salary be $x$.
Total percentage spent on electronic goods and household repairs:

$$\text{Spent}=18\%+32\%=50\%$$

Remaining salary amount:

$$\text{Remaining}=100\%-50\%=50\%$$

Out of this remaining $50\%$, he invested $42\%$ in a fixed deposit. Therefore, the remaining percentage left with him is $100\%-42\%=58\%$ of the $50\%$:

$$\text{Final Remaining Percentage}=58\%\times 50\%=29\%$$

Given that this leftover amount is $\text{Rs. }12,325$:

$$29\%\text{ of }x=12325$$

$$0.29x=12325⟹x=\frac{12325}{0.29}=42500$$

So, his monthly salary is $\text{Rs. }42,500$.

$$\text{Annual Salary}=12\times 42500=\text{Rs. }5,10,000$$