Given: The selling price of 20 articles = cost price of 25 articles Concept used: Profit % = (SP - CP)/CP × 100 Calculation: Let the Cost Price (CP) of each article be x CP of 25 articles = 25x Selling price (SP) of 20 articles = 25x Selling price of an article = 25x/20 = 5x/4 Profit = SP – CP = 5x/4 – x = x/4 Profit% = (x/4) /x × 100 = 25% ∴ The profit % obtained by the shopkeeper is 25%.