1. **State the problem:** An intelligence officer spends 40% of his salary on rent and 20% on food. He saves 1200, which is the remaining amount after these expenses. We need to find his total salary. 2. **Define variables:** Let the total salary be $S$. 3. **Express expenses and savings in terms of $S$:** - Rent = 40% of $S$ = $0.40S$ - Food = 20% of $S$ = $0.20S$ - Savings = remaining amount = $1200$ 4. **Write the equation for total salary:** Since the salary is spent on rent, food, and savings, we have: $$0.40S + 0.20S + 1200 = S$$ 5. **Simplify the equation:** $$0.60S + 1200 = S$$ 6. **Isolate $S$:** $$S - 0.60S = 1200$$ $$0.40S = 1200$$ 7. **Solve for $S$:** $$S = \frac{1200}{0.40} = 3000$$ **Final answer:** The total salary is $3000$.