Math Word Problem: Discount and Profit/Loss

To solve buying/selling word problems, you must understand three terms:

1. Marked Price (MP): The original price printed on the box or price tag.
2. Discount: The amount of money deducted from the Marked Price. (Discount is ALWAYS calculated on the Marked Price).
3. Cost Price (CP) / Selling Price (SP): The actual amount of money the buyer pays to the shopkeeper after the discount.

Let's assume a sample problem: "Vikrant buys crockery with a Marked Price of ₹5,000. The shopkeeper offers a 10% discount. Vikrant then sells it to his friend for ₹5,200. Find his Profit Percentage."

Step 1: Calculate the Discount Amount Discount = 10% of Marked Price Discount = $(10/100) \times 5000 = ₹500$.

Step 2: Calculate the Cost Price (CP) for Vikrant Cost Price = Marked Price - Discount CP = $5000 - 500 = ₹4,500$. (This is how much Vikrant actually paid from his pocket).

Step 3: Calculate the Profit Vikrant's Selling Price (SP) = ₹5,200. Since SP is greater than CP, he made a profit. Profit = $SP - CP = 5200 - 4500 = ₹700$.

Step 4: Calculate the Profit Percentage Rule: Profit percentage is ALWAYS calculated on the Cost Price (the money invested), never on the selling price. Profit % = $(Profit / CP) \times 100$ Profit % = $(700 / 4500) \times 100 = 15.55%$.