1. **Stating the problem:** A flower-girl buys roses at the rate of 4 rupees for 5 roses and sells them at 5 rupees for 4 roses. We need to find her profit percent. 2. **Understanding the problem:** - Cost Price (CP) per rose = Total cost / Number of roses bought - Selling Price (SP) per rose = Total selling price / Number of roses sold - Profit = SP - CP - Profit percent = $\frac{\text{Profit}}{\text{CP}} \times 100$ 3. **Calculate Cost Price per rose:** $$\text{CP per rose} = \frac{4}{5} = 0.8$$ rupees 4. **Calculate Selling Price per rose:** $$\text{SP per rose} = \frac{5}{4} = 1.25$$ rupees 5. **Calculate profit per rose:** $$\text{Profit} = \text{SP} - \text{CP} = 1.25 - 0.8 = 0.45$$ rupees 6. **Calculate profit percent:** $$\text{Profit percent} = \frac{0.45}{0.8} \times 100 = 56.25\%$$ **Final answer:** The flower-girl's profit percent is **56.25%**.