1. The problem asks for the percent of change in Stephen's weight after training. 2. To find the percent change, use the formula: $$\text{Percent change} = \frac{\text{Final weight} - \text{Initial weight}}{\text{Initial weight}} \times 100\%$$ 3. Substitute the given values: Initial weight = 75 kg, Final weight = 66 kg. 4. Calculate the change in weight: $$66 - 75 = -9\, \text{kg}$$ (a decrease). 5. Calculate the percent change: $$\frac{-9}{75} \times 100\% = -12\%$$ 6. A negative percentage means a decrease. So, Stephen's weight decreased by 12% after training. **Final answer:** Stephen's weight decreased by 12%.