To calculate profit percentage, we establish variables. Assume the marked price (MP) is Rs. 100 for ease of percentage calculation. A 6.25% discount is applied, resulting in a discount amount of Rs. 6.25 (6.25% of 100).
The shopkeeper's profit equals three times the discount amount. Profit = $$3 \times 6.25 = 18.75 \text{ Rs.}$$
The cost price (CP) is derived by subtracting the profit from the selling price (SP). The selling price is the marked price less the discount: Rs. 100 - Rs. 6.25 = Rs. 93.75. Consequently, $$\text{CP} = \text{SP} - \text{profit} = 93.75 - 18.75 = 75 \text{ Rs.}$$
The profit percentage is determined using the formula: $$\text{Profit Percentage} = \left(\frac{\text{Profit}}{\text{CP}}\right) \times 100 = \left(\frac{18.75}{75}\right) \times 100 = 25\%$$