A shopkeeper marked up the price of an article by 40% above cost price and he allows 25% discount on marked price. If shopkeeper earns Rs. 420 as profit, then find his profit (in Rs.) when he allows discount of 20% instead of 25%?

To find the profit when the shopkeeper allows a discount of 20% instead of 25%, we can follow these steps:

Step 1: Let's assume the cost price of the article is Rs. x.

Step 2: The shopkeeper marked up the price by 40% above the cost price, so the marked price would be x + 40% of x.

Step 3: The shopkeeper allows a discount of 25% on the marked price. Therefore, the selling price after the discount would be 75% of the marked price.

Step 4: The profit earned by the shopkeeper is the difference between the selling price and the cost price. So, the profit can be calculated as (75% of the marked price) - x.

Step 5: We are given that the profit earned is Rs. 420. Therefore, we can write the equation as (75% of the marked price) - x = 420.

Step 6: Now, let's calculate the marked price using the equation from step 5.

Step 7: Once we have the marked price, we can calculate the selling price when a discount of 20% is allowed. The selling price would be 80% of the marked price.

Step 8: Finally, we can calculate the profit earned when a discount of 20% is allowed by subtracting the cost price from the selling price.

By following these steps, we can find the profit (in Rs.) when the shopkeeper allows a discount of 20% instead of 25%.