A jacket is marked up 40% from its cost. If the cost is $30, what is the selling price?

Markup is added to cost to determine selling price. Markup = 40% of $30 = 0.40 × $30 = $12. Selling price = cost + markup = $30 + $12 = $42. Alternative: selling price = cost × (1 + markup percentage as decimal) = $30 × 1.40 = $42. The second method is faster — multiplying by 1.40 is one step. Distinguish markup from margin: markup is calculated based on cost; margin is calculated based on selling price. A 40% markup on $30 cost gives selling price $42; the margin (profit ÷ selling price) is 12/42 ≈ 28.6%. Real-world business context: retailers buy at wholesale, mark up to retail. Common markups vary by industry. Discount problems work similarly but subtract: 20% discount on $50 = $50 × (1 - 0.20) = $50 × 0.80 = $40. The 'multiply by 1.X' or 'multiply by 0.X' shortcuts save time on the ASVAB.