A trader sells an article for ₦3,600 and makes a profit of 20%. What was the cost price of the article?

If the cost price is CP, then selling price = CP × (1 + 20/100) = 1.2 × CP = 3600, so CP = 3600 ÷ 1.2 = ₦3,000. Option A (₦2,880) results from subtracting 20% of the selling price instead of the cost price, and D is the result of adding 20% to the selling price.