1. **Stating the problem:** We need to find the maximum permissible expenditure for advertising within a marketing budget of 3,000, given that design fees cost 500. 2. **Write the equation:** Let $b$ represent the maximum spending on advertising. The total marketing budget is split into advertising and design fees: $$3000 = b + 500$$ 3. **Solve the equation:** Subtract 500 from both sides to isolate $b$: $$3000 - \cancel{500} = b + \cancel{500}$$ $$2500 = b$$ 4. **Interpretation:** The maximum permissible expenditure on advertising is $b = 2500$. This means you can spend up to 2,500 on advertising while staying within the total marketing budget of 3,000.