Final answer:
To find the profit percentage, subtract the cost price from the selling price, divide the result by the cost price, and multiply by 100.
Step-by-step explanation:
To find the profit percentage, we need to know the cost price and the selling price. In this case, the dealer marks his goods at 40% above the cost price and allows a discount of 15%. Let's assume the cost price is $100. The selling price would be $100 + $40 = $140. The discount on the selling price would be 15% of $140, which is $21. Therefore, the selling price after discount is $140 - $21 = $119.
To calculate the profit percentage, we subtract the cost price from the selling price and divide the result by the cost price. Then, we multiply the quotient by 100 to get the percentage. In this case, the profit would be $119 - $100 = $19. The profit percentage would be ($19/$100) x 100 = 19%.