1. **Problem:** Wu saved 75 towards a new 250 mountain bike. What percent of the total cost of the bike has Wu saved? 2. **Formula:** To find the percentage saved, use the formula: $$\text{Percentage} = \left(\frac{\text{Part}}{\text{Whole}}\right) \times 100$$ where Part is the amount saved and Whole is the total cost. 3. **Substitute values:** $$\text{Percentage} = \left(\frac{75}{250}\right) \times 100$$ 4. **Simplify the fraction:** $$\frac{75}{250} = \frac{\cancel{75}^3}{\cancel{250}^{10}} = \frac{3}{10}$$ 5. **Calculate the percentage:** $$\frac{3}{10} \times 100 = 30$$ 6. **Answer:** Wu has saved 30 percent of the total cost of the bike.