1. **Problem Statement:** A toy is sold for 220 with a profit rate of 10% on the cost price. We need to find the cost price. 2. **Formula:** Profit percentage is given by $$\text{Profit %} = \frac{\text{Profit}}{\text{Cost Price}} \times 100$$ 3. **Important Rule:** Profit = Selling Price - Cost Price. 4. Let the cost price be $x$. 5. Given profit rate is 10%, so $$10 = \frac{220 - x}{x} \times 100$$ 6. Simplify the equation: $$10 = \frac{220 - x}{x} \times 100 \implies \frac{220 - x}{x} = \frac{10}{100} = 0.1$$ 7. Multiply both sides by $x$: $$220 - x = 0.1x$$ 8. Bring all terms involving $x$ to one side: $$220 = 0.1x + x = 1.1x$$ 9. Solve for $x$: $$x = \frac{220}{1.1} = 200$$ **Final answer:** The cost price of the toy is 200.