Two articles are sold by a shopkeeper. One of them is sold for 10% profit. Its selling price equals the cost price of the other article, which is sold for 10% loss. Find the effective profit/loss percentage approximately.

Let's denote the cost price of the first article as A and the cost price of the second article as B.

Step 1: According to the problem, the shopkeeper sells the first article for a 10% profit. This means the selling price of the first article is 110% of A.

Step 2: The problem also states that the selling price of the first article equals the cost price of the second article. Therefore, we can say that 110% of A equals B.

Step 3: The shopkeeper sells the second article for a 10% loss. This means the selling price of the second article is 90% of B.

Step 4: Since B equals 110% of A, we can substitute B in the equation from step 3 to find the selling price of the second article in terms of A. This gives us 90% of 110% of A, which equals 99% of A.

Step 5: The total cost price of both articles is A + B, which equals A + 110% of A, or 210% of A.

Step 6: The total selling price of both articles is 110% of A (from the first article) plus 99% of A (from the second article), which equals 209% of A.

Step 7: To find the effective profit or loss percentage, we subtract the total cost price from the total selling price and divide by the total cost price, then multiply by 100. This gives us ((209% of A - 210% of A) / 210% of A) * 100, which equals approximately -0.48%.

Therefore, the shopkeeper experiences an effective loss of approximately 0.48%.