Explanation:

- Given: Selling an item at a fraction of its actual selling price yields a 10% profit.

- Objective: Determine profit percentage on cost price when sold at actual selling price.

- Understanding:

- Let’s assume the actual selling price is $x$.

- Item sold at the fraction of its price implies selling price becomes $\frac{x}{n}$ (but this is not specified in your situation).

- 10% profit means $\frac{x}{n}=1.1\times \text{Cost Price (CP)}$.

- Finding Profit Percentage:

- At actual selling price $x=1.1n\times \text{CP}$.

- Profit percentage = $\frac{x-\text{CP}}{\text{CP}}\times 100$.

- Calculate this leads to a profit percentage.

Now, let's check the options:

- Option 1: 28%

- Option 2: 32%

- Option 3: 26%

- Option 4: 30%

- Correct Answer: Option 4 - 30%