Given, Cost price of an article is less than selling price by = 20% Formula: Profit = SP – CP Profit % = (Profit/CP) × 100 Calculation: Let the selling price of the article be Rs. 100 Cost price of the article = 100 × (80/100) = Rs. 80 Profit = Rs. 100 – Rs. 80=Rs.20 ∴ Profit %=(