A shopkeeper marks his goods 20% above cost price, but allows a 20% discount for cash payment. His net loss is?

Question: A shopkeeper marks his goods 20% above cost price, but allows a 20% discount for cash payment. His net loss is?

Solution:
Let
The cost price of goods = Tk. 100
Market price of goods = 120% of 100
= 120/100 × 100
= Tk. 120

At 20% discount for cash payment, real price = (100 - 20)%
= 80%

After discount selling price of goods = 80% of 120
= Tk. 96
Loss = Tk. (100 - 96) = Tk. 4

∴ Loss % = (4/100) × 100 = 4%