If the ratio of cost price and selling price of an article be as 10 : 11, the percentage of profit is 

Given:

Ratio of cost price (CP) to selling price (SP) = 10 : 11

Formula Used:

Percentage of Profit = $\left(\frac{SP - CP}{CP}\right) \times 100$

Calculation:

Let the cost price (CP) be 10 units and the selling price (SP) be 11 units.

Profit = SP - CP

⇒ Profit = 11 - 10

⇒ Profit = 1 unit

Percentage of Profit = $\left(\frac{1}{10}\right) \times 100$

⇒ Percentage of Profit = 10%

The percentage of profit is 10%.