ব্যাখ্যা
Cost price of product be Tk. 100
Marked price = (100 + 20)% of 100
= 120
Profit = 5%
⇒ Selling price = (100 + 5)% of 100
= 105
⇒ Discount = Marked price - Selling price
= 120 - 105
= 15
⇒ Discount %= (15/120) × 100
= 12.5%
∴ 12.5% is discount should be sold so as to make 5% profit.