1. **Stating the problem:** We need to create a budget for a person who wants to save 10% of her salary after moving out. 2. **Understanding the problem:** If her salary is $S$, then saving 10% means she wants to save $0.10 \times S$ each month. 3. **Budget formula:** Total expenses + Savings = Salary 4. **Expressing savings:** Savings = $0.10 \times S$ 5. **Calculating expenses:** Expenses = Salary - Savings = $S - 0.10 \times S$ 6. **Simplify expenses:** $$ \text{Expenses} = S - 0.10S = (1 - 0.10)S = 0.90S $$ 7. **Interpretation:** She can spend up to 90% of her salary on all expenses and save 10%. 8. **Example:** If her salary is 3000, then savings = $0.10 \times 3000 = 300$ and expenses = $0.90 \times 3000 = 2700$. 9. **Summary:** To save 10% of her salary, she should budget her expenses to be no more than 90% of her salary.