How many percent above should a shopkeeper mark the price of his goods than the purchase price so that he can earn 10% profit by giving 20% discount?

Let the cost price be Rs. 100. To earn 10% profit, the selling price must be Rs. 110 (after discount). Since a 20% discount is given, the marked price MP satisfies: 0.8 × MP = 110, so MP = 110/0.8 = 137.5. The markup over cost price is 137.5 - 100 = 37.5%. Option A (137.5%) represents 37.5% above cost, not 137.5% above cost as the wording suggests.