The marked price of an article is ₹ 840. A shopkeeper gives a discount of 15%…

Concept: A discount is a percentage reduction on the marked price that produces the selling price: selling price = marked price × (1 − discount%/100). Profit percentage, however, is always defined relative to the cost price, not the marked price: selling price = cost price × (1 + profit%/100). So once the selling price is known, cost price = selling price ÷ (1 + profit%/100).

Application:

1. Selling price after a 15% discount on the ₹840 marked price: selling price = 840 × (1 − 15/100) = 840 × 0.85 = ₹714.

2. The 19% profit is on the cost price, so selling price = cost price × 1.19. Substituting selling price = ₹714: cost price = 714 ÷ 1.19 = ₹600.

Cross-check: With cost price = ₹600, 19% profit on it is ₹114, giving selling price = 600 + 114 = ₹714 — exactly the selling price obtained from the marked price and the 15% discount, confirming ₹600.