Every child's first instinct when sales are slow is to cut the price. It usually works — more people buy. And it very often makes the day worse, because a 20% discount is not 20% off the price, it is closer to half your profit.
Discount = marked price × rate ÷ 100. Selling price = marked price − discount. A Class 8 student can do this in a line.
The hard part is what the answer means, and no textbook question ever asks.
Your cost does not fall when you discount. So the whole discount comes out of the gap between cost and price — which is your profit.
A glass costing ₹7 sold at ₹12 makes ₹5. Discount it 20% and you sell at ₹9.60, making ₹2.60. The price fell by a fifth. The profit fell by almost half.
That asymmetry is the single most useful thing a Class 8 student can take out of this chapter, and it is the reason a busy discount day can still end in a loss.
The discount is only worth it if it brings enough extra customers to cover the profit it destroys. That is a calculation, not a hunch — and it is one most adults never do.
In Lemonade Empire your child runs a lemonade cart and uses this exact concept to decide what to buy and what to charge. Free, no signup, plays in a browser.
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