Given: Number of articles brought = 6 Cost price of 6 articles = Rs. 8 Number of articles sold = 10 Selling price of 10 articles = Rs. 12 Concept: First, equal the number of articles sold and brought so that the cost price of the number of articles sold can be determined. Then calculate the profit or loss percentage. Formula used: Loss % =[(CP−SP)/CP]×100 Calculation: Taking LCM of the number of articles sold and brought; We get 30. ∴ CP of 30 articles =8×5=Rs40 SP of 30 articles =12×3=Rs.36 ∴ Loss % =[(40−36)/40]×100 ⇒(4/40)×100 ⇒100/10 ⇒ 10% ∴ His percentage of loss is 10%