the correct answerThe cost price of 18 articles is equal to the selling price of 15 articles. The gain percent is?

Sure, let's solve this step by step:

Step 1: Understand the problem The cost price of 18 articles is equal to the selling price of 15 articles. This means that the seller is making a profit because they are selling 15 articles for the price of 18.

Step 2: Set up the equation Let's denote the cost price of one article as 'C' and the selling price of one article as 'S'. According to the problem, we have the equation: 18C = 15S.

Step 3: Solve for 'S' To find the selling price 'S', we can rearrange the equation to solve for 'S': S = 18C / 15.

Step 4: Find the profit The profit is the selling price 'S' minus the cost price 'C'. So, Profit = S - C = 18C / 15 - C = (18C - 15C) / 15 = 3C / 15 = C / 5.

Step 5: Find the profit percentage The profit percentage is the profit divided by the cost price, times 100%. So, Profit% = (Profit / C) * 100% = (C / 5C) * 100% = 20%.

So, the gain percent is 20%.